About the last thing Reno had expected right then was for Rufus to charge him. It was a logical enough conclusion when Rufus hadn't shot him; if the man had been planning on killing him, the way to do it was with a gun. It had already been thoroughly established that Rufus shouldn't be able to take Reno in hand-to-hand combat. So for a split second, the Turk was too surprised to react, and found himself being slammed against a wall.
Oh good, he thought, decided not to shoot me so he's just going to beat me up, inste-- Huh?
Okay, so if he hadn't expected Rufus to charge him, the concept of Rufus kissing him was akin to being struck by lightning. His mind shut down for a moment--though his lips, without any shred of his conscious knowledge, readily responded to the intrusion--before pulling itself back together enough for him to make an attempt at shoving Rufus away from him, at the very least succeeding in getting his mouth free.