Why does MaIIinson get so frustrated? (Chapter Four)

Mallinson becomes frustrated because their departure is delayed. He simply wants to leave and get home as soon as possible.

“But something has GOT to be arranged! We’ve all got our work to return to, and our friends and relatives will be worrying about us. We simply MUST return. We’re obliged to you for receiving us like this, but we really can’t slack about here doing nothing. If it’s at all feasible, we should like to set out not later than tomorrow. I expect there are a good many of your people who would volunteer to escort us — we should make it well worth their while, of course.”