Nice one! Keep it up!
When he looks around the corner of the door, it happens rather quickly. I'm not sure what the action should be but maybe it would look better if he stayed at the positon of looking left (his right) just a few frames. I hope you understand what I mean.
From what I've observed people seem to turn their eyes before they turn their head when looking at something.
I'm not an animation guru so don't take these comments too seriously