Having heard the State's case and evidence. I don't think they have proved beyond reasonable doubt that OP's claim that he thought there was an intruder is a lie, and that he fired at the toilet door knowing that Reeva was in there.
So I think the judge will have to consider the evidence on the basis that OP DID think that there was an intruder in the toilet. Being sure in his mind that there was an intruder in the toilet, was it reckless (or worse) to have fired 4 shots at the door? Many would say "YES" without much hesitation, but OP's actions will be viewed in the context of the circumstances of this particular event.
His defense will likely be that he was in fear for his life and his gf's life. This is South Africa where home invasion, torture, rape and murder are not unknown. People do live in fear to some extent. In gated communities, with bars on windows, alarms and fences etc and armed guards patrolling at night. Many people do legally own a gun for self defense (that is...own a gun for killing intruders, should the need arise). OP is a paraplegic and so likely grew up feeling somewhat vulnerable (psychological state different from the norm). He is in fact vulnerable to some extent especially while not wearing his prostheses. Less able to flee. He may also argue that retreat and fleeing would have amounted to abandoning Reeva to the "intruder". In a panicked state he fired. Did he have actual intent to KILL the intruder? If it is accepted that OP had a genuine belief that there was an intruder, the Judge will have to decide if that was what a reasonable person might believe in the circumstances. She also has to evaluate OP's reaction to that belief, which was to fire at the toilet door thinking that an intruder was behind it.
I don't think that Nel has given her much "assistance" in deciding these matters. Maybe he will (finally) with his last few witnesses?
I imagine that Roux will be putting a lot before the Judge to sway her decisions