Port: Merge pull request 7007 from VOREStation/aro-teleshuttle

Adds an overmap shuttle to medical

code/modules/overmap/sectors.dm

@@ -6,6 +6,7 @@
 	scannable = TRUE
 
 	var/list/map_z = list()
+	var/list/extra_z_levels //if you need to manually insist that these z-levels are part of this sector, for things like edge-of-map step trigger transitions rather than multi-z complexes
 
 	var/list/initial_generic_waypoints //store landmark_tag of landmarks that should be added to the actual lists below on init.
 	var/list/initial_restricted_waypoints //For use with non-automatic landmarks (automatic ones add themselves).
@@ -58,6 +59,8 @@
 
 /obj/effect/overmap/visitable/proc/find_z_levels()
 	map_z = GetConnectedZlevels(z)
+	if(LAZYLEN(extra_z_levels))
+		map_z |= extra_z_levels
 
 /obj/effect/overmap/visitable/proc/register_z_levels()
 	for(var/zlevel in map_z)