He had cuts on his hands, so could he have grabbed the knife after he was shot?
Did she point the gun at him when he was in the shower, he grabbed the gun, he (a former wrestler) deflected the shot from the center of his head to the side of his head? Was he shot in the shower, lunged out, she stabbed him in the back several times as he leaned over the sink and as he crawled down the hall towards the top of the stairs, she slit his throat at the end of hallway. The gun shot seems more likely to have come first. A knife in the heart first ... wouldn't he have dropped dead at the foot of the shower, and would a wrestler have been able to deflect a woman with a knife from stabbing him in the heart first? He doesn't seem to have enough injuries on his hands for a full fledged knife attack defense.
I think that she meant to shoot him in the head and have him drop to the foot of the bathtub, but instead she pulled the gun, he grabbed it and turned her hands enough to deflect the shot to the side of his head. Then he probably lunged toward her and that's why the gun was no longer in her control after one shot (she claims that she dropped it). That's when she pulled the knife, an apparent back up plan. He most likely grabbed the sink when he realized that he'd been shot, bled all over the place, and realized that she was now stabbing him in the back ... maybe he turned and grabbed the knife before crawling down the hallway and died when she slit his throat ... all within 62 seconds. Then she dragged him down the hallway - now in a fog because things didn't go as planned - to the bathtub where she had it all planned out. His getting away and down the hall was not in her "alternate reality".