The Moogle avoided the arrow and stopped mi_d-air as Cloud protected himself.

"Firaga-Ja!"

The moogle cast the fire spell on Yuna, Sephiroth and Cloud-- Cloud would be spared its effects thanks to Runic, but not so much for Sephiroth and Yuna. Even then, as the Moogle stopped to cast the spell, it would give a chance for Sephiroth to reach him or Yuna's second arrow to hit him.