Randy was a technician in one other unit at the base in which Angel, Saul, and Michael were stationed - that is what we learned with #41-2 ...
Since Roberts was a scientist of exceptional skill, I think it is very unlikely that Randy and Roberts had a professional connection with each other; but that does not necessarily mean that maybe they met as friends or shared the same hobby - you know, like roleplaying games or shit ...

Anyway: Since #41-2 we also know that Randy was wounded by a regular; and because Randy was a "hell of a smart guy" (according to Michael) and because Randy did so many cool things ever since he has been a zombodroid, it is a rather safe assumption that he is a smart one. But: He has become a zombodroid about 1 1/2 months after the zombocalypse kicked in.

Q1: Did he enlist to become one of Ink's men? Or:
Q2: Is he kind of rampaging solitary guy with a small group of regulars carin' for his own businesses?

I think: Q1. But I am not so certain (anymore).

Best wishes!
Liam