I'll take a stab at it. I'm not saying that I think this is true, just that it is a possible scenario based on the evidence presented in court so far.
Oscar wakes up in the middle of the night and goes out to the balcony to bring in the fan. His getting up wakes up Reeva, who gets up to pee. Oscar is on the balcony and doesn't hear her get out of bed. As he comes back in, he hears noises in the bathroom and freaks out.
The bedroom is pitch black, and when bedspreads are lumped up on the bed it can be really hard to tell in the dark if someone else is in bed. Oscar grabs his gun and starts yelling.
Reeva is in the bathroom and hears Oscar yelling about an intruder. She is probably terrified and has no idea he thinks she is the intruder. She figures her best bet is to hide in the toilet and keep quiet. Maybe she had locked the door out of habit when she went to pee (that's fairly common for girls to do, even when at home or with a loved one), or maybe she locked it when she heard the yelling. By the time the bullets came through the door, everything happened so fast. She may have never known it was Oscar who shot her, she might have believed it was an intruder.
It was horribly irresponsible for Oscar to shoot through the bathroom door, and even if this story is true, he deserves to be locked up for committing a terrible crime.[/quote]
Not a bad stab at it (as implausible as it all seems). As we saw with OJ, it is amazing what a good defense team can come up with. The trial may come down to a few other things that have been reported, but not necessarily presented in court yet:
1) What forensics says about the bloody cricket bat (and Reeva's crushed skull)
2) If forensics proves she was shot once prior to entering the bathroom. Surely she would have yelled/screamed at him to stop. It obviously took a bit before he entered the bathroom and shot her through the door.
3) Reports that police had been called to the house 2 hours prior to the shooting because of an argument the couple was having. Additionally, it is reported that after the shooting he first called his family, police were alerted by a neighbor. Neither of these two prove murder, but they certainly fit the prosecution's narative significantly better than his.