is there strange message behavior when a lich is killed by a fall? (from Rapid Brogue)

[MattWeiner]

This issue appeared in a game of Rapid Brogue but it seemed likely that it would manifest in CE, so I'm reporting it here in case you can check it out.

brogue.roguelikelike.com/#viewRecording/RAPIDBROGUEV130-630d75d4c7b84926599d48f6 turns 4500-4501

Near-death lich hit with a potion of descent gives the following sequence:

As the flask shatters, the ground vanishes! The lich plunges out of sight! The phylactery appears. The phylactery plunges out of sight!

This seems like it must be an effect of the code for killing a monster as the result of a fall, but doesn't seem like the right sequence of messages.

(As a suggestion, I think it would be good for the message to say when a monster is killed by a fall--"The goblin plunges to its death!"--but that's a suggestion and I don't know how easy it would be to implement.)