Help With Final Mission (SPOILER ALERT!!!!!)*****

In Aftershock:

I'm having trouble with the final mission to the M*** base. I've got my squad there no problem, fought my way across the landscape to the lift that takes you into the base, then fought the Rets inside the base, killed them all no problem.
Now, when I go all the way to the lowest level, I see the 3 M**m's on the wall, and they all have red arrows above the block that is above them.
I've tried every possible damage type, from splash to warp to projectile, and nothing in that room can I damage. I'm at a loss as what to do. The "Next Area" button is able to be pressed, but there isn't an exit grid on the map and the teleporters just take you to the middle/upper level. When I try to press the button, it says none of my soldiers are in the exit area. Help! I've scoured the forums for information, but I haven't found anything to help.

Sincerely,

Raeven.