Nevermind, I've found out.
SomeDude, you cannot DISARM it, however you can get past it:
First, go back to the starting room (one with the morning puzzle) and search for a rock. Once you find it, go back to that lightning room entrance and throw a rock there, you will see that there are actually three rays of electricity flashing on and off.
Wait until there's not a single ray of electricity on the screen, and run through. But do it quickly, then.
