Here is an idea: Go with that kind of a Resident Evil route of expendable resource allowing you to escape a “grab”.
What that could be? Boot knife. Every single marine gets one chance to break from xeno grab even if stunned, knife gets stuck in a runner for example, gets lost and that runner can’t grab anyone for a couple of seconds.
Thats it. Second xeno can try to grab you, or that first can wait out his cooldown.
Knife has to be in your boots, maybe make it a normal-sized item and it would be perfect.