Hopefully not one that has been suggested here before; it's a fairly simple one. Note that for the sake of convenience, I'll be using my fanon names for the Sergeant (Austin del Rosario) and the Security Officer (Vincent Callahan).
Vincent is Austin's descendant, or perhaps reincarnation (or both, though I'm starting to lean towards the latter--either makes whatever Anomalous Pyramid-related deja vu Vincent gets more plausible).
While I like complexity as much as the next person, there are some matters on which I prefer things be kept simple. This option allows me to link those two without risking straining suspension of disbelief by trying to explain how Austin survived to the 2100s, or how the UESC/G could recycle people that hard. And didn't that terminal on "Kill Your Television" allude to reincarnation or something akin to it?..
(I'm also thinking that Vincent is a later generation of battleroid, one who didn't receive the faulty programming that caused the first gen to go berserk, but that's another story)