BIB, to add to this, I believe Roux recognized that Masipa didn't accept PPD. However, the next step was intent and since there was no intent, Masipa went for CH.
What the PT did was they adjusted their complaint and said that there was error in objecto and the fact that it wasn't Reva in the bathroom, doesn't make a difference, OP still planned on killing whoever was in there and that's why it's murder.
So essentially, we need to determine what was OP's intent that night and that's tough. What was his exact intent the moment he was standing right in front of the door.
There is nothing that can say beyond a reasonable doubt what was going through his mind in terms of intent. To me, the bullets loaded in the gun don't make a difference, what's to say he wasn't going tomorrow to shoot some more watermelons with his friends the next day? Nel never asked him AFAIK.
Yes, if he stood in front of the door for a few minutes before shooting, then he should have had the foresight that his actions could have killed someone, but as Roux explained it in his closing when he slammed his hand on the table, he said there was a noise, OP got startled and shot.