What was Valhallarama thinking at the end of Book 10?

I know why Valhallarama tried to kill Hiccup in the beginning of the tenth book; she didn't know who he was. But why did she kidnap him after he got the dragon jewel? Was it just so she could tell him how much she loved him? She didn't have to do that with Alvin and Excelenor watching though did she? What was she thinking? Can anyone please help me?