Of course … This was on the premise that they could take care of these four in one fell swoop. If he could not, then Qin Yu's move would be the best of the best.
Long Yueling and Yingsuiyue both felt that this was the only option available to them, and that they could only win "quickly". Just like when he was dealing with the four elders, he was already dead before they could even react.
Because Qin Yu wasn't actually the most difficult to deal with, the most difficult to deal with was Qin Zhixing. It was not because Zhixing was as strong as she was, but because in Yingsuiyue's heart, she could not kill Zhixing. On the other hand, dealing with Qin Yu was different.