cannot complete this mission period. the last two squad i see before the final spatial charge are one shotting any support that beams in, a single captain has zero chance of surviving the damage long enough to even kill one of the 3 in these squads let alone the whole squad.
Even if as a tac i use tac team and then use tac inititiave so i can bring in another set of security they down them too qucikly to kill the squad which resets if you don't kill them all. so again game progression halting due to a bug. and i'm unable to find a workaround this bug.
I ran into this problem as well- after being one shotted several times I lured the Romulan squad toward a nearby squad of friendly Remans , who were promtly killed( all with one shot). I was barely able to pass using even this method, and hey- I'm sweet in ground combat!
for some reason the remans arent being scaled up to the quest level.... i fixed this by when i see the beam in anim, do an AOE attack that hits all the romulans.... it draws them off of the remans long enough to beam in and start attacking. then i took out the weaker romulans first. they annihilated me but at least it was down to two guys., so the next time i went in, i beat them by myself.