at 19:30 when she breaks down a bit, I believe her. She said:
"he was kneeling down in the shower...and I don't really know what happened after that"
Her body language before she says that is believable. I did not know she ever said he was kneeling down before just now.
I always said he either bent over toward the shower head, or bent down, the shot went through the right eye brown in a downward motion exit left cheek.
I say she shot first, he kneels down, she lifts the gun shoots him through the right temple expecting a fatal shot through the temple. He was below her (hence all the blood low in the shower) Because he was kneeling the bullet didn't go straight through his head, it went down at an angle, not a fatal shot, simply due to his kneeling.
I think he surprised her by stumbling to his feet, he got up, he was dazed but then tried to fight back.
Then the frenzy ensued with the knife.
http://www.youtube.com/watch?feature=player_embedded&v=FoUB2UzWjtI#!
18:20 on...at 19:05 you see her relive the first shot she fired. She feels it