locs[] is only ever going to have turfs in it, and it will only have more than one turf in it if the bounding box is greater than one tile in size, if I understand the documentation right.

The other alternative is to override this function in the code for each multi-tile object which in this case is just the door.  That reduces a small bit of overhead for each call because it isn't checking the locs list; however, if other multi-tile objects are added, the function has to be overridden for each.

Either's fine by me