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/game/objects/structures/lattice.dm

@@ -84,4 +84,4 @@
 
 /obj/structure/lattice/singularity_pull(S, current_size)
 	if(current_size >= STAGE_FOUR)
-		Destroy()
+		qdel(src)

code/game/objects/structures/mineral_doors.dm

@@ -24,7 +24,7 @@
 
 	Destroy()
 		air_update_turf(1)
-		..()
+		return ..()
 
 	Move()
 		var/turf/T = loc

code/game/objects/structures/segway.dm

@@ -112,7 +112,7 @@
 	if(health <= 0)
 		if(buckled_mob)
 			buckled_mob << "The [src.name] was destroyed!"
-		Destroy()
+		qdel(src)
 
 /obj/item/sec_seg_key
 	name = "security segway key"