This encyclopaedia contains lots of spoilers - you should play through the campaigns first before reading too much here!
Safe Haven
mentioned in cam2_8a.ogg:
In the event of further strikes you are to establish a safe haven for the evacuation of Beta Base. This location lies outside the blast zone of the largest nuclear missile. Eradicate any enemy and secure the area.
also mentioned in c2diif2.ogg, its where the commander is told to head to after evacuating beta base