Some flaws...

[RoyaleBeast]

Well I never thought that he cut off his hand. I thought that when he started to cut off his hand the immune system that was resisting the infection was trying to focus less on the infection and more on the hand that was being cut. Thus the infection saw the perfect time to take control. Also I thought that was just a chuck of skin and organs that flew out of the window when he mutated. It's like in RE5 when someone mutates into a bigger monster. They freaking explode and I assumed that's kinda what had happened since the transformation was so quick.