His testimony about how he got into the toilet room after killing RS didn't sound right imo.
I'm more inclined to think he had had the key all along and after not only terrorizing RS for upwards of 15 minutes(gun shots through the bedroom door, her jeans pulled off inside out at the foot of the bed(bruises on RS's thighs), another pair of jeans tossed out the bathroom window, screaming at her to "get the *advertiser censored** out of my house! get the *advertiser censored** out of my house!", the bashing of the bathroom(metal plate, tiles, toilet door) and then the final four shots that killed her likely while she had either been trying to get out of the locked room or trying to hold the door shut against him.
That would explain why she hadn't called anyone even if she did have her cell with her, would explain why the keys in the door didn't appear bloody, would explain how convoluted his explanation was of how he broke the door down and got the keys, yet the one big plank in the toilet room was lying partly over the threshold and there were large splinters of wood in the toilet bowl that RS had supposedly been draped over.
It would also explain why he pulled her out of there(I think he may have pushed/pulled the panels out while the door was open and she had already been pulled out) and why so much blood was in the bathroom where, according to his explanation, they shouldn't have left the big pools that were there. It would also explain the rumours that her car had been sitting running in the driveway, her bag had been packed ready to leave, and according to one media source her valentine card had been tossed aside carelessly. MOO
http://www.channel4.com/news/oscar-pistorius-guns-reeva-steenkamp-court
"A Valentine's card addressed to Ozzie carelessly thrown nearby."
[video=youtube;qx5ibmqsiR4]https://www.youtube.com/watch?v=qx5ibmqsiR4[/video]