After crawling under the house and taking a closer look, I think they actually were feeding on a large piece of plywood that was sitting on the ground. I think when the alates emerged they happened to crawl up the brick and into the wall. Pretty lucky break.
I've had a colony of giganteus for a few years now and it's population seems to wax and wane dramatically. At one point overrun and now I probably only have 10 adults and a decent number of nymphs. This has happened before but I never hammered down the cause. Enclosure is a sterility bin about the size of a 20 gal with maybe 4 inches of substrate with lots of cork bark.
Anyone else had issues with tormentosa overrunning enclosures or otherwise causing issues with other species? My Vonones ornata colony stopped producing once the tormentosa numbers rose. After rehousing them they began producing again which makes me think the isopods were eating the eggs. They also infested my A gigas cage which made me have to set up a whole new cage up. They seem to be fine in my roach cages though.