Actions:
Unit Group - Pick every unit in (Units in ''Rect'' <gen>) and do (Unit - Make (Picked unit) Invulnerable)
Wait 600.00 seconds
Unit Group - Pick every unit in (Units in ''Rect'' <gen>) and do (Unit - Make (Picked unit) Vulnerable)
But if the units you want to make vulnerable again, are not standing in that rect anymore, you'll have to use a variable, to save the unit group. When the 10 minutes are over, make that unit group vulnerable again (not whatever units are standing in your rect).