[Maybe because meeting his powers leaves one entirely exposed, vulnerable, as though he's seeing right into your soul. Like he could destroy it if he wanted to.]
[The only good point about it being he doesn't want to, which means there's no incoming illusion of dragon claws and teeth ripping you apart, no stopping your heart. Instead it's Shinah struggling to regain control of those powers, to stop them before they do any real damage he doesn't want done.]