Ash had been alive a long time but he had never once seen tears. Vampires didn't have tear ducts; when they were upset, they howled in rage and went on some sort of rampage of destruction to get their feelings out. He was not equipped to handle tears.
A lot of things he didn't know how to handle had happened tonight. Being dressed as a female was bad enough. Kissing someone for the first time in centuries and liking it more than he thought he would was even worse. But Ruby's tears took the cake.
He didn't understand why she was so upset. She had already run away from her uncle once before; what was the difference between doing it once as opposed to twice?
Was it because he kissed her? The thought wasn't a pleasant one but this might be his fault. She claimed it wasn't but she might hate him now. He couldn't bear that! Not when she was the only one left he cared about.