Like Tmmk stated, you don’t get back to Sanctum at all. The UI is completely hung, except for the debug menu stuff. Landscape disappears, but in an odd way. I recall when it happened when changing characters at my home, my view ended up pointed at some storage blocks. I couldn’t see the blocks themselves, but I could see the items on them. For ones a little further away, I saw silhouettes of items. There are further silhouettes which are items on shop stands, but no shop stands visible.
When I died and was attempting to “return here,” all I could see was sky.
Oooh. I just remembered I sent a screenshot of that to a friend because I was just kind of going “wut.” For whatever reason, it didn’t occur to be to report it. I guess I figured it was a one-off kind of thing.