"It seems to be an ability he's able to pull off when he's took a considerable amount of damage." Limit breaks not being an unknown, in his own World after all - but Sephiroth doesn't want Ib to think too much into the events surrounding the last time that Luffy had 'popped'-

"What I'm trying to say is-"

He pauses for a beat, to perhaps reconsider how he should put this but then decides that there is no other way around the fact.

"-you were helping him get to that point. That move was a decisive turning point in the battle."