You are conceding an easement on Peter's property rights, though, which is violative of Rothbard's natural law principles. Which is fine. I believe such easements must exist, as well. But I'd argue this is a fatal blow to anarcho-capitalist political theory, more generally if you think through the implications of granting this easement based on circumstances. It means the NAP and self-ownership model is not completely self-consistent, and special accordance's need to be made at the limit. So you've really conceded my point.
Discussion
Then the question will have to turn to: who decides what those easements are, and what the consequences are if they're not afforded? Then you find yourself in a bit of a pickle: you either admit that the landowner, and his security forces and the disaffected people who don't want to be thrown in the ocean have to work it out on the street with violence to sort of the easement of the right. Or you just stop being utopian and accept something like a democracy where these rules for easements can be hashed out in a uniform way.