Excellent post Hope. I don't think OP had the time or presence of mind to think how he was going to cover things up. Especially in the frame of mind he was in at the time, and the eye witness accounts of his emotional state.
I believe that it was himself he was worried about when he ventured into the bathroom and Reeva would have been an afterthought, but he can't say that in court can he? Something else struck me from the very beginning and I have never mentioned it before because it is difficult to put into words the feeling I have about it. It was the witness account of how OP was pleading with god to let Reeva live, and trying to make a bargain with god by promising to be a good person etc. (I can't remember exactly what he said), if he would let Reeva live.
This strikes me as real. I don't know if anyone else on here has tried to bargain with god in times of great worry or grief. I have, more than once, and to me, that heart rending plea coming from a person's mouth is real. I know many will say that he was just pleading to be saved from jail, but it strikes me as being genuine.