09.00 Derman is back on the stand first thing this morning, being questioned by Kenny Oldwadge for the defence, with Barry Roux sitting back for this final stretch. When court adjourned on Wednesday afternoon, Derman was getting to the crux of his evidence: that people who suffer from anxiety may struggle to control automatic responses to what they perceive as a threat.

This point is being presented in tandem with the suggestion that Pistorius, as a disabled person, had a justifiably raised fear of physical attacks because there is evidence to show that disabled people are more at risk for physical attacks.

Derman has so far come across as a strong and convincing witness, with the defence taking pains to stress his lengthy and impressive CV to the court. We can expect Gerrie Nel to want to take his time to tear down his evidence.

11.30 Tea-time at the Pistorius trial, with the defence’s Kenny Oldwadge having concluded his questioning of witness Wayne Derman and turned him over to the state for cross-examination.

Derman continued today in a similar vein to yesterday afternoon, dealing with the “fight or flight” reflex in people who are anxious. Oldwadge asked him to explain the apparent contradiction between Pistorius’s physical vulnerability and his choice in this instance to confront danger. Derman said it was consistent with the “fight” impulse, such as a mother approaching a predator to protect offspring.

Oldwadge read from Pistorius’s testimony on the stand, where the athlete said he was “not thinking” when he fired his gun. Derman explained that “thinking” in this context is a function of the neo-cortex, responsible for executive function. But when the fight or flight response kicks in, there is decreased cortical function.

Why would Pistorius not choose “flight” instead of “fight”?

It wasn’t an option, Derman replied. Pistorius has no lower legs. His only option was to fight. Derman described it was an “understandable physiological phenomenon”. The noises in the bathroom which Pistorius thought he heard – a door closing, a window opening – would have triggered his fight or flight response. Later Derman also mentioned that the “startle” reflex, accentuated in anxious individuals, would also be heightened in conditions of darkness.

Derman also suggested that as an athlete, Pistorius was primed to respond quickly to sounds due to conditioning from the starter gun in a race.

Derman sought to tackle the “paradox” of Pistorius: how a man ranked as one of the 18 fastest athletes in the world could also be described as physically vulnerable. Pistorius is “supremely able but significantly disabled”, Derman said. He then cited a long list of tasks that able-bodied people take for granted but that disabled people would struggle with: dressing, showering, being intimate and so on.

In short, Derman said, Pistorious would respond to a perceived threat with a degree of fear that might seem extraordinary for an able-bodied person, but which would be normal for a disabled person. The athlete’s “exaggerated fight response” was responsible for “this horrific tragedy”, Derman concluded.

Derman also put in his two cents’ worth about the issue of athlete Arnu Fourie moving rooms at the Paralympic Games, which local broadcaster David O’Sullivan has said was explained to him by Fourie as being motivated by a desire to escape Pistorius’s loud and angry phonecalls.

Derman said that Fourie had consulted with him a few days before a crucial race because he had the beginnings of a respiratory virus. Derman had thus recommended that Fourie move rooms. The story about the phone arguments was, he said, “news to him”.

O’Sullivan, meanwhile, has left a lengthy comment on yesterday’s Daily Maverick trial summary elaborating on – and maintaining – his version. In it, he says that the content of Pistorius’s aggressive phonecalls was made up of fights with girlfriend Sam Taylor, and that this was confirmed by other athletes.

Gerrie Nel now has his go at cross-examining Derman, which he is likely to do at length. In his opening sallies, he has been suggesting that Derman’s testimony cannot be seen as objective because Derman was Pistorius’s physician, and even suggested that Derman should not be giving evidence.

When we adjourned for tea, Derman was explaining his process of consulting with Pistorius prior to giving evidence. Derman consulted twice with the athlete, once before the trial commenced and once about a week before Pistorius’s psychological evaluation. Nel is grilling Derman about his note-taking and note-keeping during this process.

13.00 After tea, Nel asked Derman to clarify what his purpose was in giving evidence. Was Derman saying that Pistorius’s anxiety and disability explained why Pistorius shot Reeva Steenkamp? Derman prevaricated, saying that the court “can use my report in any way they see fit”.

Nel proceeded to quiz Derman on how the process of startle-fight/flight fitted into Pistorius’s account of his movements up till the moment he shot through the door. Derman explained that while the startle response would be immediate, the fight or flight response time would vary.

Derman said that the first startle Pistorius experienced would have been the sound of the window knocking against its frame in the bathroom. So Pistorius’s fight/flight response was getting his gun, Nel wanted to know. No, he froze first, Derman replied.

Would one startle be enough for the flight or fight response to control all Pistorius’s actions until he fired his gun? Derman responded that there would need to be more than one startle because of the time that elapsed after the initial startle. Over time, Derman said, the fight or flight response would abate and “physiology would return to baseline”.

Nel went through the actions taken by Pistorius after hearing a first noise: remembering where he had left his gun, finding his gun, taking it out of its holster. His implication was clearly that all of this required more conscious thought over a longer period than would be expected from the fight or flight theory. Derman clarified that there would be some cognitive function happening during flight or fight, just that it would be diminished.

Nel tried to get Derman to map the stages of startle, fight/flight on to Pistorius’s movements to the toilet door. At what point in the process would one require a second startle to sustain the fight/flight response? Derman said he couldn’t give a time period.

“If there was only one startle, and the accused acted as he did…he would have acted outside the fight or flight response?” Nel asked. Derman replied that he wouldn’t be in a position to know this. Nel insisted that earlier Derman had said that there would need to be more than one startle.

“Because that’s what happened,” Derman replied (ie, that there were two further noises which evoked a startle response from Pistorius). In other words, Derman was strangely unwilling to entertain any possibilities outside of what Pistorius specified happened.

It’s been an extremely fractious session, characterized by hostile exchanges between Derman and Nel. On more than one occasion Derman asked Judge Masipa for assistance against Nel, but at least once Masipa instructed him to get on with answering Nel’s questions.

“If you cannot assist because you don’t know, just say you don’t know,” Masipa told Derman.

15.00 After lunch, a rather tedious debate continued. Nel had asked Derman before the break about Pistorius “arming himself”, which Derman had misheard as “calming himself”. Derman had said that Pistorius was not at all calm at that time, and that he wished to correct something in the record – the idea that Pistorius had “run” towards the threat. Derman said he had clarified with Pistorius that in fact Pistorius had moved with one hand against the wall for balance.

Nel said that nobody had ever claimed that Pistorius ran down the passage, and that Derman just wanted to bring this up on his own. The two sides proceeded to tussle over whether the record stated that Pistorius had run or walked down the passage. Judge Masipa eventually called an end to it by saying that the record should be produced in this regard on Monday.

Derman continued to say that he felt it important to clarify that Pistorius is not capable of running on his stumps, as he has witnessed.  Derman had asked Pistorius to demonstrate how he moved down the passage, and Pistorius showed that he had walked with his right hand at shoulder height holding the gun in front of him and his left hand cupping the wall for support.

This led Nel to a small victory. You might recall that when Pistorius testified, he was at pains never to say that he “intended” to shoot someone with his gun – because in South African criminal law intent has to be established. Nel suggested to Derman that if Pistorius was walking down the passage in fight mode – as Derman has maintained – with his gun in front of him, the obvious inference was that he intended to shoot.

“His intention was to shoot whoever he comes across, if he comes across someone.”

Derman somewhat reluctantly agreed that this was the case.

Nel pushed this further later, getting Derman to agree that Pistorius fired at the sound he heard from the toilet. When Nel asked Derman why Pistorius fired (wanting to get into the cause-and-effect of a startle response), Derman said that he couldn’t answer that.

Derman could not recall what the second startle – the noise of the toilet door closing, on Pistorius’s version – had caused Pistorius to do, saying he couldn’t be expected to be so familiar with the record. Nel accused Derman of “trying to fit the facts to the startles”. Derman denied this.

Nel asked Judge Masipa for an adjournment till Monday to consult with a psychiatrist, apparently the author of Pistorius’s Weskoppies psychiatric report. Masipa granted this.

Till then, we have a weekend to think about startles, fights and flights. And as much as Wayne Derman may wish to take flight from Gerrie Nel’s cross-examination, he has to stay to fight another day. DM

Photo: South African paralympian Oscar Pistorius during his murder trial at the High Court in Pretoria, South Africa, 02 July 2014. Pistorius is accused of murdering his girlfriend Reeva Steenkamp on Valentine’s day in 2013. EPA/WERNER BEUKES / POOL