Get regen up on the tank and medica 2 on the party, use largesse first if it's available to make the regens more potent, then use holy to stun all the mobs (DRKs will hate you but no one likes them either). Aero 3, since holy stun will overlap and be resisted if you do it back to back on the first one, then just holy spam, benediction or Tetragrammation if the tanks hp drops too low (less than 50%). Assize or lucid dreaming when mp gets too low. Things should die quickly unless dps are asleep, if they are, reapply regens and pop asylum.