It's definitely possible (some weren't so sure). The clue for the numbers to enter into the box the first time is on the bench, and the clue for the 4-character sequence is out the peephole. You just have to look around really, really carefully or the focus goes right off of it. The posters do nothing, but moving the fuse around is a bit important (though if you need the alarm, I can't tell it - just the lights and the door from what I can tell, though I did have it in the alarm for awhile so it -might- have done something I just wasn't aware of).
Nice game! :-)