Same deal with royal palace: wiped out minions including 4 heavies (with the aid of handily-emplaced mortar and HMG, since I didn't bring an RPG). One alarm set off, no choppers, no capture, so I looted it and left. I did get Yummy's fort on 2nd try though, chopper came after I sniped/bolted the locals, and I got it with on-premises RPG. Cool thing about the palace is there's no way in except to fly over in a buzzer (improbably not drawing anyone's attention) and crash-land on the cliff behind it.
EDITED: 5 Jan 2019 15:54 by DSMITHHFX