if 173 gets caught in the door frame, he will not move from there, no matter how many times you blink.
However, if you back up near the monitor and blink or turn away, you'll hear scraping, and this usually means he's back re performing his circle algorithm.
If that don't work, open the door, blink, pull him out, close and open door again, while staring at him, run thru the lock room and keep staring at his direction until the door closes.

Haha I've been having this same problem lately. Well, I wouldn't exactly call it a problem, as at that time the game was a lot less stressful! ;)