Merge pull request #10701 from Ghommie/Ghommie-cit527

Ported further runtime fixes by AnturK.

code/datums/diseases/advance/advance.dm

@@ -110,7 +110,7 @@
 // Randomly pick a symptom to activate.
 /datum/disease/advance/stage_act()
 	..()
-	if(carrier)
+	if(carrier || QDELETED(src)) // Could be cured in parent call.
 		return
 
 	if(symptoms && symptoms.len)

code/datums/traits/_quirk.dm

@@ -15,6 +15,7 @@
 /datum/quirk/New(mob/living/quirk_mob, spawn_effects)
 	if(!quirk_mob || (human_only && !ishuman(quirk_mob)) || quirk_mob.has_quirk(type))
 		qdel(src)
+		return
 	quirk_holder = quirk_mob
 	SSquirks.quirk_objects += src
 	to_chat(quirk_holder, gain_text)