On the hidden lab level (the one where you first encounter an explosive crate), I've got to the door on the upper level, but it doesn't open!?! What did I miss?

I'm talking about this level. As far as I can tell, I didn't miss anything from the walkthrough so I don't know why it won't open.

Nevermind, now I see it. You have to activate the screen (with the hand print) on the computer to open the door. I'd assumed it was just background decoration.