I'm stuck in the factory...in the room with the computer that tells you to revisit all of F1-2's rooms once the power is out, there's a locked door to the left, and I have no keycards. I remember getting 2 keycards from the conveyor belt rooms with the Wizrobes, one from the chest that you need the Steel Plate to get to, one from that robotic fish enemy, and I think another keycard (though I forgot where I got it). So, I'm pretty much stuck at the room with a green sign at the left, missing a keycard.
Do I have to do something with that air vent thing in the room with all the spikes and flame generators? Any help as to where I can find other keycards would be appreciated.