Something was brought to my attention so here is a note about the update for everyone but todeswind.
If you decide to attack back and defend yourself, the enemy will basically have you swarmed rather than it being a confrontation you can still back out of. So if you stick around any longer than the initial disengagement to escape them and run, then you'll be stuck there.
Their batons are strong enough that if they hit you mid-leg or so it would freeze up the knee, cause the leg muscles to fail for a moment, or something of the leg. Just enough to stop you from really fleeing.
With that said, If you choose the run option, you certainly may harm some of them, but its meant to be more of a shoving them off action. We just all know what an Astartes body shoving a normal man can mean.
Even though you can kill all of them, by the time that happens it will lead into the next update, so there isn't meant to be time for you to take everyone out and then also run.
You can never be prepared for the unexpected