"Oh, uh, actually... " Barry turns around and on cue Caitlin steps out of her lab, a metal tray in her hands.

"Oh good, you're here," she says, casting a sunny smile on Yamato.

Barry steps aside to let her pass as she heads straight for Yamato.

"Sorry, dude," Barry says, the reason for his apology possibly evident given that Caitlin's tray has everything necessary to give one a shot.