There was something about that somber expression that made Zacharias want to take hold of Merlin and tickle his sides until he laughed. But as that would be a rather strange thing to do at the moment, he held back.
"Hello," he said instead, and he grinned in his usual easy way. "Drink later?" he suggested, because he wanted to get out before it got dark. Not that they didn't have plenty of time, but drinks could be distracting.
He waited for Merlin to get his cloak, and held out his hand. "I'll Apparate us to where we're going."