I'm just going to throw this out there just in case anyone doesn't know: Xenos are incapable of escaping containment cells without outside assistance. As long as no one pushes that button, they are simply free defcon that is as good as neutered. Killed containment xenos is only a detriment to the marine side. Even IF xenos hijack and make it up to the almayer, chances of rescue are slim to none, as a crusher is required, and needs a VERY particular line to charge down.
Killing containment xenos is only removing RP for the researchers, CMO, and CL, and on top of this it is the only chance they have to fight back or escape. Please stop this, it makes rounds a lot less entertaining, and the only danger the breeding involves is when you open those doors to try and kill them.