There's a game out there where some vampires shiftshape in various ways - going to mist form, earth melding, things like that...
Which led to a drain in a basement floor. It's drain pipe was cracked and on the other side of the crack was an earthen area - one that had been hollowed out someone by tunneling rats (also controlled by the vampire). The vampire entered the basement (which was made up as a death trap), turned to mist, floated down the drain, then merged with the earth - but only if he had enough blood in his system to do it. Otherwise he had backups that would serve as decoys if he was hurting for blood...
When it comes to cunning creatures - like Black Court Vampires who have survived for decades with everyone knowing their weaknesses - there is no level of paranoia that is too much. No level of planning that goes too far. The stupid and unlucky, they didn't survive, so you're dealing with those who are fittest at surviving.
Richard