"We." Robin echoed Eddie at the same time, and for the exact same reason. Vecna snatched Nancy; it had nothing to do with them. It was Vecna and Vecna alone. Not that that would stop Steve from feeling terrible about it. Or lost. Or like there was a hundred other things he could have done to keep her from being "chosen" by that asshole.
Robin nodded to Eddie, as if he would understand that she was answering on specific question, on whether or not Eleven was the girl with the powers. Or the girl without the powers, as it were now. But now wasn't the time to mention that.