Like an idiot, Roxas will take that opportunity and use it to light that special little present Shin gifted him earlier. Why not.

While huffing on it, getting the end started so it will burn and he can inhale, as Shin goes to the edge, despite the slight inebriation held he's immediately on the defense here. Springing to action, like nothing was holding him back, he's right there by Shin's side at the edge. Just in case.

If he had to, he'd jump right down too. Why? ...that's just the kind of person he is.

"Hey.. how about we make sure that doesn't happen? Let's.. come back, away from the edge. Hm?" As gently as he can, he tries to bring Shin back closer towards home base. Whatever that is.