[ now it's dipper's turn to stop and blink. ] Wait - yeah, I mean, that's right, but - "still called San Francisco"? [ was hiro from the future where san francisco was renamed something else? or the future in an alternate world, at least. }

Sounds like it probably hadn't been too long since someone was there. That, or they left in a hurry. Maybe both. [ griffin fur is an especially odd clue in this mystery. why that? ] Were there any other clues left behind? Anything that might identify who was there? Any vehicle tracks outside? [ why keep a secret operating room on top of a mountain? it obviously wasn't reclusive enough to escape notice if it was abandoned in such a way. ]