Fix remaining non-returning Destroys()

Plus a little refactor to mining flaps and spacepod doors- they now use
CanAtmosPass instead of manually setting the turf to no-atmos-passing

code/modules/mob/living/carbon/brain/brain.dm

@@ -20,7 +20,7 @@
 			if(stat!=DEAD)	//If not dead.
 				death(1)	//Brains can die again. AND THEY SHOULD AHA HA HA HA HA HA
 			ghostize()		//Ghostize checks for key so nothing else is necessary.
-		..()
+		return ..()
 
 	say_understands(var/other)//Goddamn is this hackish, but this say code is so odd
 		if (istype(other, /mob/living/silicon/ai))

code/modules/mob/living/simple_animal/friendly/spiderbot.dm

@@ -216,8 +216,8 @@
 	held_item = null
 
 	robogibs(src.loc, viruses)
-	src.Destroy()
-	return
+	qdel(src)
+
 //Cannibalized from the parrot mob. ~Zuhayr
 
 /mob/living/simple_animal/spiderbot/verb/drop_held_item()