Meanwhile… no, wait, this chapter just continues the last chapter.
The old man tells Arthur not to be worried, that he's totally safe. When Arthur asks about the missiles that almost killed them all, the old man notes that the computers do that sometimes because they're bored.
The old man also explains that the Magratheans aren't dead. They're just sleeping until the economy recovers enough for them to start selling their services again and building custom planets.
Also, back when the Magratheans were awake, the old man's favorite thing was to make fjords.
The old man tells Arthur to follow him or he'll be "late." And by "late," he means "dead."
So they get into the old man's aircar, where the old man finally introduces himself. His name is Slartibartfast.