lazy fix

code/modules/power/supermatter/supermatter.dm

@@ -368,6 +368,8 @@ GLOBAL_DATUM(main_supermatter_engine, /obj/machinery/power/supermatter_crystal)
 	var/speaking = "[emergency_alert] The supermatter has reached critical integrity failure. Emergency causality destabilization field has been activated."
 	radio.talk_into(src, speaking, common_channel, language = get_selected_language())
 	for(var/i in SUPERMATTER_COUNTDOWN_TIME to 0 step -10)
+		if(QDELETED(src))
+			return
 		if(damage < explosion_point) // Cutting it a bit close there engineers
 			radio.talk_into(src, "[safe_alert] Failsafe has been disengaged.", common_channel)
 			final_countdown = FALSE