Help to opening a locked door ...

[frognum]

I'm stuck in the door that have a blood legend or something that, and there are two laser beams and three explosives (a guy dead on the floor, too)... then I go to the next room (the door is behind two metal shelfs) and I heard the tape, but I can open the electric box or the door with the blood prints in the floor in front of it ...

Help please, I know that's is the very beginning of the demo, but I tried everything ...