She finally looks back at him if only to give him an annoyed glare for that tap dancer comment. She's just trying to use logic here! That...was decisively not logical. She probably would have vocalized her complaint had he not continued.

Those later comments remind her about just how much she still doesn't know about the world she left. Echo hadn't even been able to properly focus on the real problem for long and she has no idea what happened, but given her lack of success in questioning Oz she's pretty sure Xerxes Break is not going to prove to be an easy font of knowledge. It's probably best to stick to the topics at hand, or at least things that had been mentioned.

"Understood." At least, probably as much as she's going to be able to right now. After a pause, she adds "What did your previous comment concerning the Will of the Abyss mean?"