Even with it being no more than an inch or two, as soon as his feet leave the ground, Zexion panics. It might be more mental than any true emotion but the simple fact of the matter is that this is far too similar to a situation he never wanted to happen to him. Vanitas or Riku's Replica, it doesn't matter. He cannot and will not allow himself to die.

Nor does he think for a change. His thoughts are frantically running around his mind and so he does the next best thing. He reacts; he still has his strength.

The attack isn't physical. He has no weapons that are physically capable of crossing the distance and he can't think straight enough to both summon his Lexicon and change its form anyway. Instead, he opts for something quick and dirty and reflexive. A blast of illusionary pain, every bit as real as Vanita's mind makes it - and he's quite sure he would have no reason not to as invisible claws stab into his chest; his heart. The last bastion of any thinking being's self no matter what it was.