Sure, the grout one or the firebrick one? The tunnels are pretty large in both nests, they were designed to hold Camponotus or Formica comfortably. Lots of room for them expand.
Nothing is getting out of the firebrick one, short of Veromessor chewing their way out.
They won't get out of the grout one either. The entire backing is sealed, and I am not sure they can even fit into the crack. Brachmyrmex might fit into the crack, but they still wouldn't be able to escape