[MIRROR] More deletion cleanup (#1112)

* More deletion cleanup (#53681)

- Observer mobs not delling correctly
- AI delling basically nothing
- pods not delling glow effect
- minor slime cleanup

* More deletion cleanup

Co-authored-by: TiviPlus <57223640+TiviPlus@users.noreply.github.com>

code/modules/mob/living/silicon/ai/ai.dm

@@ -39,10 +39,11 @@
 	var/can_be_carded = TRUE
 	var/alarms = list("Motion"=list(), "Fire"=list(), "Atmosphere"=list(), "Power"=list(), "Camera"=list(), "Burglar"=list())
 	var/viewalerts = 0
-	var/icon/holo_icon//Default is assigned when AI is created.
+	var/icon/holo_icon //Default is assigned when AI is created.
 	var/obj/vehicle/sealed/mecha/controlled_mech //For controlled_mech a mech, to determine whether to relaymove or use the AI eye.
 	var/radio_enabled = TRUE //Determins if a carded AI can speak with its built in radio or not.
 	radiomod = ";" //AIs will, by default, state their laws on the internal radio.
+	///Used as a fake multitoool in tcomms machinery
 	var/obj/item/multitool/aiMulti
 	var/mob/living/simple_animal/bot/Bot
 	var/tracking = FALSE //this is 1 if the AI is currently tracking somebody, but the track has not yet been completed.
@@ -193,10 +194,18 @@
 	GLOB.ai_list -= src
 	GLOB.shuttle_caller_list -= src
 	SSshuttle.autoEvac()
-	qdel(eyeobj) // No AI, no Eye
+	QDEL_NULL(eyeobj) // No AI, no Eye
+	QDEL_NULL(spark_system)
+	QDEL_NULL(malf_picker)
+	QDEL_NULL(doomsday_device)
+	QDEL_NULL(robot_control)
+	QDEL_NULL(aiMulti)
 	malfhack = null
-
-	. = ..()
+	current = null
+	Bot = null
+	controlled_mech = null
+	linked_core = null
+	return ..()
 
 /// Removes all malfunction-related abilities from the AI
 /mob/living/silicon/ai/proc/remove_malf_abilities()

code/modules/mob/living/simple_animal/slime/slime.dm

@@ -109,8 +109,7 @@
 		AC.Remove(src)
 	Target = null
 	Leader = null
-	Friends.Cut()
-	speech_buffer.Cut()
+	Friends = null
 	return ..()
 
 /mob/living/simple_animal/slime/proc/set_colour(new_colour)

code/modules/mob/living/ventcrawling.dm

@@ -69,7 +69,7 @@ GLOBAL_LIST_INIT(ventcrawl_machinery, typecacheof(list(
 	if(buckled)
 		to_chat(src, "<i>I can't vent crawl while feeding...</i>")
 		return
-	..()
+	return ..()
 
 
 /mob/living/proc/add_ventcrawl(obj/machinery/atmospherics/starting_machine)