Kiryu was likely smacked with a blow that would have floored a normal man... Unfortunately, or Fortunately for Uzaki, Kiryu was no normal man... A blow like that just triggers "Battle mode".
Those were battle instincts that Uzaki triggered... Which imply she slapped him so hard that the blow would have floored a normal man... Unfortunately, or Fortunately for Uzaki, Kiryu is no normal man.
