Factory ought to be larger than an office building. Folks have been debating making assembly lines, etc; I imagine that the CVD unit in the lab finale is a good starting point.
Couple thoughts:
Rivtech firearms & ammo are Proprietary. Their production facilities ought to be pretty secure; automated versions of their product might not be out of the question.
Rivtech has a consumer-products division. If dodging 8mm caseless turrets isn’t feasible for your character, you might still be able to load up a few pallet loads of atomic energy drink, that atomic coffee maker you always dreamed of owning but could never afford, and enough atomic nightlights that you’d never worry about lighting your underground base again.
(Plutonium cells could likely be found in the supply lines. Not sure about iodine.)
I’m not sure where Rivtech would locate their plants; it’s possible that they’re someplace outside the scope of DDA. That’s not my call to make. (But a factory would ruin the “Rivtech is Rare” balancing factor.)
The critters certainly seem interesting, though I’m not sure the RM13 would be available to every guard on the floor. Extant zed-scientists would likely be present in the R&D sections, for instance. Tankbots might be present both as a security measure and as test subjects: just how effective is the LMG?
[hr]
Reference to one’s name != megalomania. There’s a difference between “This needs a name and I don’t have any ideas, may as well put my mine on it” and “I am KA101, best contributor ever! Look on my works, ye n00b, and despair!”