Stuck in room with 3 laser beams

[tuakka]

I'm kinda stuck in the room with three laser beams (to the right there is a man in a room with a gasmask on). Already tried a lot of things, but whenever I try go to go over the beams, the bomb detonates.
Hope somebody can help me!

Actually, it's better if you just turn the lasers off altogether. All you have to do is go to one of the ends of the laser, crouch down, and you'll see a small box on the wall past the lasers. Place your pointer on the box and double click. This will bring up a screen with red colored "+" (plus signs) on the left and green colored "-" (dashes) on the right. To turn of the lasers, you need to get both sides to be green "-" (dashes). When you press a red "+", it turns into a green
"-", but it also turns one of the green "-" on the right into a red "+" . This puzzle is random, so you'll need to figure out which red "+" on the left controls which green "-" on the right. This puzzle is available for all lasers. Good Luck!