Yeah I can't see it tearing down the message pipe, that would exit the app.

But what it is doing is first posting a message that will call `[NSApp stop]` then calling `[NSApp run]`. Which is odd, because `[NSApp nextEvent]` exists, but even if that doesn't work it's not the way I'd do it. However I'm sure there are very good reasons to do it this way when you know the emacs source.