He had trouble listening to others explaining, in detail, how his bullets killed Reeva Steenkamp. He couldn't quite make it through his first day of testimony before a merciful judge called a halt to proceedings. But those were always going to be mere appetisers to the main challenge Oscar Pistorius is yet to face: cross-examination by determined and well-prepared prosecutor Gerrie Nel.
And Pistorius is not making life any easier for himself.
In his initial sessions in the witness box this week, Pistorius opened up areas that, under the rules and habits that prevail in normal criminal trials, would have remained unexplored. But due to the peculiarities in Pistorius's defence, right from the night Steenkamp died (and a high-powered lawyer was summoned to the scene), the prosecution team has five lines of questioning beckoning in an inviting fashion.
Why apologise from the witness box?
In the majority of criminal trials, the time for apologies is after the verdict, lawyers agree, when mitigation becomes the sole focus, and when contrition becomes important. Apologies are also popular in parole applications.
Pistorius, on the other hand, offered an apology to the Steenkamp family before giving evidence in a move that has left some perplexed. "If I had an accused come to me and say 'let me apologise at the beginning' I would stop him right there," said an advocate not involved in the matter.
Because Pistorius made the apology as part of formal proceedings, lawyers said, Nel may interrogate it. Was it aimed at the watching world rather than the family? Did it take more than a year for Pistorius to feel remorse, or did he simply not feel it necessary to express that remorse? Did anyone suggest an apology may be in order?
How does memory improve over time?
Pistorius this week explained he had been "scared" and "overcome with fear" on the night he shot Steenkamp, yet could recall much of the events of the next several minutes in detail: when he screamed, how he held his gun, what he thought at various times. Other crucial detail he could not remember, such as when he switched on lights that would have revealed Steenkamp was not in the bed where he expected her to be.
The differences between the sequence of events Pistorius narrated in court, that which is contained in his detailed plea explanation, and that contained in his March 2013 statement – and the fact that each version was more complete and coherent – will likely take up several sessions and see Pistorius sorely pressed.
Why are other people lying?
Two witnesses, under oath and threat of perjury, told the court that Pistorius fired a gun through an open sunroof. Pistorius offers no events that could have been misconstrued and no explanation, simply a flat denial that the incident ever happened. The inescapable implication is that two people conspired against Pistorius, knowing the potential consequences, for opaque reasons.
The charge related to firing the gun is of minor consequence, experts say, but shaking Pistorius's version of events feeds into his overall credibility – and on that credibility, a verdict could hinge.
A closer look at character
Guided only broadly with questions about his upbringing and home life by defence advocate Barry Roux, Pistorius shared many details that reflect on his character: his faith, his work with the disabled, his love of animals. Legal experts were this week divided on whether that would allow Nel to call new character (or, rather, anti-character) witnesses of his own, but the consensus was that Nel could rightfully delve deeply into Pistorius character during cross-examination.
What is it about Pistorius that makes, by his account, so many of his former friends willing to lie under oath to persecute him? Has he ever been accused of verbal or physical abuse? How does he reconcile his faith with his alleged attempts to shift blame for his actions on to others?
Just how vulnerable is 'vulnerable'?
Without his prostheses on, Pistorius told the court, he feels particularly vulnerable to crime and violence, which he considers ever-present threats. To the extent that speaks to his state of mind, such heightened fear could be crucial in a final verdict.
But Pistorius also told the court that he moved fans about a room without his prostheses and ran while wielding a gun. Fear need not be rational to influence behaviour, but a world-class athlete in superb physical condition and well versed in the use of firearms may still find himself explaining that fear.