Mihila didn't expect Soverick to cry or feel the pain of Kayla's death like her but she expected him to at least pretend to feel something. He doesn't even need to pretend for a long time, just for her short burial ceremony. Then he can resume whatever he is doing.
Soverick said to them, "Look here. So what that she died? I am not going to pretend I care about her. I didn't pretend when she was alive. I have much less reason to pretend now that she is dead. She wasn't special when she was alive and her death is not special either. People die every day and I don't care about that. Why should I care about some random person that I was in close proximity with for less than 2 years?"