Indeed they do... it is all because the good/evil genus that infected them, sometimes piety shows up from inside them and they dont want to hurt you plenty.
How about we assume theese guys run off Doom I and II rules?
I hate it when enemies pick up phase devices, maybe even more than i hate them picking up large med packs.
Lets just be glad that none of them spawn on Phobos Arena.
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P.S, Kornel: The quote button is broken ("Access Denied")