While it remains true that the cats hate each other and fear the bun, there is something else going on. The bun, teething with particular ferocity yesterday, was completely inconsolable. Max, the Cat With Attitude, who is unusually neurotic and generally of the "me-first" cat set, was maiowing with vehemence outside the bun's door when he was in his meltdown. Whether it was keening in sympathy or distress I'm not sure.
All I know is that when I opened the door, Max was on the other side. And when the bun, who was almost purple with tears, saw the cat he was completely distracted. Max didn't let him pet him, but he did stick around long enough to make sure that he was mollified.
The other cat has done this too. So even though they've devised meticulous plans of retreat in the basement, they also care for the small ape we're so preoccupied with.
Or maybe they just want him to be quiet.