On an occasion where Dr. Ravichandran is away from his office (Sans will wait until one of those moments when he sees him leaving for those meetings he's late for, or whatever it actually might be), Sans is going to try to force his door open with a credit card. He'll wait until nobody else is in the hallway of course, and he won't try too many times since he doesn't want to draw attention here.

Edit to note that while Sans will make sure he sees Dr. Ravichandran leave, he will make sure Dr. Ravichandran doesn't see him.