i was wondering if it was volontary that you didn't implement any triggerbomb that when a unit come closeby would explode?
This could be of great help to secure a building/room after you searched it so no alien would enter there without triggering the bomb.
Similarly alien could set some of them when you are too slow to reach the crash site.
These trigger could be of similar types as the grenades (flash, smoke, plasma, ...)
of course soldier could spot it, if good "perception test" performed, or if equiped with a detector (clearly that would be a new extra). And could maybe disarm them? But maybe this is going away from the guerilla fight style...
