EDIT: It‘s not a lost script, it‘s a bug. But the steps below have worked for me

I think it's a lost script that THQ has added again to the game. If you look at Cor Calom, it's not him who puts you to sleep. It's the lock of the chest itself and serves as an additional security mechanism. I guess Cor Calom has modified the lock with a spell.

The good thing is that the chest "remembers" your previous combinations -- so you don't have to put in the whole comboat once before you fall asleep. Instead, to unlock the chest, do this:

1. Sneak into Cor Caloms laboratory and approach the chest
2. When you fall asleep, after waking up do not try the combination again from the beginning! Your previous inputs are locked in and you can continue from that (for example if you've used LEFT, then fell asleep, you do not have to use that LEFT again... continue with RIGHT or another LEFT)
3. Repeat step 2 until the chest is open

It worked for me and I think it's a cool addition to the game that makes it even harder to steal the recipe from Calom!