I know, I could go on and on and on with these little inconsistencies, like Mark wearing no shoes, and in the next scene, he does, and the first SAW-movie contains a lot more of those little 'errors', if you like, but I won't go on and on..
They're just minor things, details, that's all..
Don't get it twisted, however, I am and will always stay one of the most huge, biggest SAW-fans..