Galahad sees no reason not to take Magnus at his word regarding touch -- if Magnus is like Percival in so many other things, then he's probably as likely to be honest. He nods, too, at the idea of Magnus accidentally losing control of his powers when he's overwhelmed, which feels of a kind with Galahad's holy fire, even if he's only been upset enough to use it once.

He processes you're safe a moment later and looks back at Magnus in surprise.