I would say that it represents a rat king. The detail that the rats open or close the door makes it even more interesting.
I also think they are forming one. I was merely pondering whether the emblem shows "the rat king" with whatever symbolic implication the artist wanted to convey with this, or if it shows "rats forming a rat king" symbolising Cazador's dominance over other creatures, forcing them to sacrifice themselves (once knotted together, they can't move anymore and are doomed) to protect his sanctuary, possibly foreshadowing the ritual. Just me overthinking and admiring the problem. =)
I guess, we can't all be Toreador. Did guests even see the patterns on the door? I can't recall which way they open. The doors might always be open for them when they enter and if they are allowed to leave. I doubt his parties were very fun though, the whole palace has this air of dusty severity.
Maybe there's a mail-order-catalogue for sinister types: Stone amphoras, available in black, petrol and purple, limited supply only.
Imagine the shame, your grand temple sharing the same decor as the seedy palace of some stuck up, petty vampire lord, who banns whistling.
