Nice callback to Spiteful's arson attempt earlier.
It also reminds us again that, as cute and friendly Squee is, she's still part of a psychopath. In a sense, Art's right in that everyone's version of Squee would be psychopathic as there's nothing to moderate it and steer people away from/towards things that would make them unhappy, including when those unhappy things involve hurting other people.
I wonder if they've considered some way to scan the tunnels to make sure they've found all the pieces of Hilary, sort of a biometric resonator tuned to Hilary's distinct bioelectric signals. You know, so they can be sure they're not overlooking, say, Hilary's conscience manifesting as a bunny-shaped flea. (Minuscule, occasionally slightly itchy, and sometimes raises a little bump or two, but otherwise ignored as if it wasn't there.)