When the Heartless appeared, he simply drew his gun to his hand. There were a plethora of items around for him to use as cover if need be, but he was not actively geared for combat in his Yin formation just yet, especially against those who might come in close. As such, he dodged to the side of an oncoming Bandit, letting its scimitar slice the air beside him before aiming at its head and firing while it was recovering from the attempt. The bullet, not infused with a lot of his power, and thus not very powerful itself, sent the Heartless sprawling, but another shot to the chest was needed for him to send it evaporating into smoky darkness, its heart flying away.
A turn to one of the red ones, floating in the air, as it let loose a fireball in his direction. The young man was forced to duck to get underneath it, shooting again, this time with more force, as it let another free. The second of the fireballs exploded right in front of it, seemingly doing no damage at all, but he followed up with two more, each to the approximate area of the insignia on its torso. As it crashed into a wall, evidently dazed, he took a deep breath, realizing that as he was, his Yin style would not suffice. Instead of rushing in, he stepped back as the yellow one attempted to headbutt him, trying to spend a bit of time out of combat, and focused.
He would only need a few moments, but he still would require the time to switch things up.
(He'll be back to fighting soon. You two can use this opportunity to test out some more skills if needed, or otherwise show how good [or alternatively how BAD if that works better] they are at combat right now.)