[He makes a noise. That's really the best response he's got right now, coupled with a gentle squeeze over her shoulders. It's no surprise that Tyki continued to provoke his attacker, just like it's no surprise that Kitty managed to talk Cross down. It's also not very hard to guess how this must make her feel right about now — they had similar situations back home and that usually didn't involve someone you knew.
In the end, he settles for a comforting cliché. Softly. What else can you say?]