That early discovery of this form of hers had made training with Cassie all that more interesting, rather than just ignoring her in his early days on the train, having shoved her aside into the typical human category. And she was improving with it, with more access to a 'god' energy to fight against. It's why even if this was a chance for her to work off some anger, Vegeta's not going to just accept those hits. She would still have to work for it.

But also not pushing as much as he may with them training. This wasn't really a chance to learn, just to use fighting as a stress relief and to land those hits. More reinforcing past training. And of course some taunting, since Cassie can take it. "I thought I told you to give it your all, not to warm up."