What a relief!, that's not my door. Not that I have any experience, but maybe a bigger knife would make things easier (and a little less light could also help).
I like the idea, but I keep jumping back and forth between the door knob and the knife. I'd like it better if the light was more on the knife than the knob.
Seems like you have two central points of interest here. The door knob, and the knife. The door knife is lacking focus from either motion blur or DOF. Otherwise, this is a good photo and a nice take on the challenge.
I would suggest trying to fix the lighting a little here... the whole center of the photo is lost in black, making it somehow feel a little subjectless. Good shot, otherwise.