So I was wandering along in Hell today building myself a nice bridge ready to kill the WOF, when suddenly above me I noticed some nice blue bricks. Upon closer inspection I realised that it was actually the very lowest point of the dungeon. I tunnelled through and so now have a (handy?) back door into the dungeon but it got me wondering:
If I hadn't already killed Skeletron, what would have happened? I assume I'd be killed at some by the guardian things, but where? I had to tunnel through a fairly thick wall so at some point half way through the wall would I suddenly become "in the dungeon"?