Time can't be any factor in fairly fast paced video game. You can't get shoot in the leg in S.T.A.L.K.E.R. and then lie several months to recover in Skadovs, or walk with splint for the rest of the game. Still, I find it easier to belive to brought back a marine from death, than create things out of thin air. Do you?
Benos don't even have organs and they are not slowet down by constant barrage of bullets. Marines in comparsion are Arma level gig vs two 5 year old's playing with Aliens (TM) toys.