My B.colloseus went straight out of the shipping container from Matt and into their bin. I've never moved or messed with them other than to pull the bin down and throw in some food. There have never been any escapes or questionable incidents of any kind and they are on the other side of my roach room from my other Blaberus with 4 hungry tokays, glue traps and roach bait in between.
It is within the realm of physical possibility that "something" happened, but very very unlikely. Even if they found a way to climb up and out of their smooth-sided bins, they would have to run the gaunlet, cross the room, get back up to the shelves, climb up the smooth sides of the other bins, and squeeze in through the closed lid. Its also possible that I wouldn't notice two different species in the same bin, but again, not likely.
These are pretty old specimens. Probably the originals as this species is one of the few that didn't do well for me. I've got fusca, craniifer and discoids coming out my ears, but these, the giganteus and E. decipiens just haven't done well for some reason.
Also, I've only ever received three shipments of roaches, the last one was in January of this year. One from James T., one from Matt K. and one from Zephyr.