Important advice for clearing the room from the above entrance:
Click here to view the secret text
×When placing the first decoy, make sure you catch the two southeast roaches in its field of influence. This will stop them from going into the alcove east of the exit passage. If they get in there, you'll never be able to make progress.
Place the second decoy at (17,8), facing NW. This kills a queen, but more importantly it also prevents a guard from getting into her tile and killing the decoy. This particular placement leads to guards getting trapped, and makes things a lot easier.
Now you have to actually get out into the room. You can either slowly kill everything in your way, or try to manipulate guards into killing enough roaches to give you an opening.
Either way, once you're out the next step is to remotely manipulate guards into killing queens on the west side. Further decoys aren't too important; I did a test run just now where I used them to kill queens while also plugging up the holes in my roach traps.
When the west queens are gone, you can make your way to the trapdoor (after hitting the pressure plates, of course). This is a slow process, but not too bad if you can prevent any roach spawns from getting in the way.
After dropping the trapdoor, the cleanup process isn't too bad. I saved a decoy for this and used it to kill a queen in the particularly crowded east side.
