I have tested this in the AH3 Beta, and what happens is that if you drop troops at your own town or vehicle base where the guns are down, you get a message saying "Map room xxx destroyed, it will be down for 30 minutes" but no capture message. Then, enemy troops cannot capture that base for that 30 minutes (by which time the guns are usually back up). However, if the ProtectObjects flag is set in the environment settings ArenaFlags, then your troops don't destroy your map room and the base can be captured by enemy troops, even within the 10 minute "troop life" time. So it seems that this is simply a result of the Beta being set to allow destroying friendly objects, and (presumably) it will not work when ProtectObjects turned on.