There is also the whole problem of how a lot of marines *will* suicide once captured, and it is almost impossible to stop them.
Hell, I think I have burst in a planetside non-dropship hive all of 3 or 4 times ever, and one of those was only because I foolishly chose to try to escape instead of suiciding into the fire left behind by the CAS strike I called in on an ovi'd queen (past tense) via flare. I would imagine it is pretty discouraging to see three quarters of the marines coming in either suicide nading, calling in CAS on themselves, drug ODing, standing in their own flamer fire or buckshotting their head off, and that is when they aren't robustos who go on a rampage around a hive with a magharn shotty and several grenades.