Yuya is absolutely ecstatic. Completely relieved that it worked. Not that he didn't believe Alphys, but... it sure wasn't an easy solution back home.

"You did it!" He pumps his fist in the air, before remembering that those people are probably dazed and confused and still need some help. He reaches for one of them, grabbing their hands tight to help them up. "Easy--you're okay now."