× For the hard way here: what places would be relatively safe in this room?

×Clearly, we can't kill enough roaches per turn. Thus, we'll need to kill queens instead of roaches whenever possible.

Head to the top corner, killing as many queens as possible. If you have to kill roaches, do it in a manner that gets you up to the top.

Now, get preferably one row of roaches.

Turn one, move over as many queens as you can, killing roaches. By the halfway mark, start moving back, killing nothing but queens. You should be in the corner by the next spawn cycle.

In this manner, you can clear out enough roaches to get breathing space to clear a corner. Continue in this manner, and, well.