Vanitas lifts up both of his knees and Riku braces, his stomach tightens on reflex. His knees still drive the breath out of him in a hard grunt, his kick pushes him back into the wall. He's lucky that the pegs holding the life preservers to the wall narrowly misses punching him in the kidney, the impact sends some of these floats thudding to the floor.

There is no flash of light when Riku summons Braveheart, there hasn't been since he arrived on this world, it's too narrow in this space to fight with a weapon of this size and that isn't the point.

He drives it forward to cleave in twain the shimmer of black that Vanitas launched at him. It splits, slaps a pair of scorch marks into the wall to either side and one of the life preservers smolders instead of burns, still too damp from recent use, the humidity in the air. No longer does the question of why matter. Vanitas is here for a fight.

Pushing off from the wall with a grunt, Riku's overhead swing is limited - he can't bring it all the way back, there isn't room - but his strength is brought to bear with the aim of driving his blade down to lock with Voidgear. And then, blade-locked and grappling, to aim Vanitas' back to the open doorway.

There's no guile here, he's trying to maneuver for an advantage and Riku expects Vanitas will be doing the same. Even as furious as he is, as hurt, he fights with predatory instinct and those instincts have proven formidable in battle.