Board Thread:Episode Discussion/@comment-34633327-20180120015359/@comment-26397825-20180122010051

I think it's because Yang came up alone with the relic when they know Cinder and Raven (who they thought was not on RWBY's side). Basically in their minds, Yang was really intimidating for not only coming back aliv, but coming back without a scratch and the relic in hand. They basically went 'Oh Shit.'

If they'd had more time to think about it, they probably would have realised that Yang didn't fight.