I'll start with the obvious ones, let's see if anyone can come up with something more creative.

1. Bite your tongue really hard right before the end of every work day. Then...
2. Bang your head against the wall, where your hair is, so no one can see the bruising, but hard and frequent enough that your outtie always has a headache when they get done work.
3. Cut yourself where no one else will see. Like on your leg. Just enough to leave a scar.
4. [1-3] Generally all the same idea. Gradually increase covert self-harm until your outtie realizes that your work self will eventually do something drastic and irreversible if you don't quit. If necessary, cut off a tip of one of your fingers.

Okay, not very creative, I know.

I can't think of anything else though. I was thinking maybe a USB drive with a text file on it, but I'm guessing the elevator is probably designed to detect those as well. Any more creative ideas?