The thought of Frodo and Sam in Mordor doesn't help to cheer him. He knows everyone – especially hobbits – is meant to be confident of victory, but it gets harder with every blow they suffer, and if Merry's too weak even to stand, how can he hold up anyone else?

Oh, Merry. He takes on too much, he really does. And it was so horrible for him, losing Theoden, and soon he will be separated from Pippin again, and nearly all of his friends. This is a lovely glimpse of that.