Add an IsDead check to prevent crashes in survival01

mods/ra/maps/survival01/survival01.lua

@@ -66,6 +66,7 @@ SovietBuildings = { Barrack1, SubPen, RadarDome, AdvancedPowerPlant1, AdvancedPo
 IdleTrigger = function(units, dest)
 	Utils.Do(units, function(unit)
 
+		if not unit.IsDead then
 			Trigger.OnIdle(unit, function()
 				local bool = Utils.All(units, function(unit) return unit.IsIdle end)
 				if bool then
@@ -80,6 +81,7 @@ IdleTrigger = function(units, dest)
 			Trigger.OnCapture(unit, function()
 				Trigger.ClearAll(unit)
 			end)
+		end
 	end)
 end