Agreed. The team from CJ's tower that went to
the Arena in an attempted rescue of
Samantha, and
Kalani is unknown.
Randy and the techies must have been ordered out sometime between Kalani's arrival and the over running of
the other tower (three days window). One caveat I'd like to issue though Nik is that we can't safely assume Randy was alive when
Michael ran into him. Although it is a very likely chance Randy was alive at the time, we also have to allow for the possibility that Michael had a run in with a zombie Randy who could have been sporting a name tag; he could be a mechanic with overalls sporting his name, or even an engineer of some sort who still sports his name badge out of pride for his former job.
Though I am more inclined to believe he was alive when Michael ran into him so that we can get a bit of flashback story from Mikey later down the line.