At no point during the video did any Russian soldier posture themselves in a position which would indicate submission or surrender.
My guess is the mobniks ran out of ammo and were trying to escape.
Looks like there are several dead ones lying in the trench behind the active Orc shooters, and it didn’t help that one got shot in the head.
They were all either dead or wounded; there was no where to go because the next stretch of the trench is straight.