"On the off-chance something like that were to happen, yes," he says with a faint smile.

It's only when Mizu makes a motion to return it that Vergil will dismiss the blade. He has no issue with Mizu taking his time to inspect and admire the blade, and doing with as he wills with it. It's not as though Mizu could do anything to damage it and he certainly doesn't have command over it to begin tearing Vergil's apartment apart. Not that he thinks Mizu would consider the latter even if it were possible. Limiting themselves to just a training session with no weapons had been more out of respect for Vergil's space than concern for his still healing injuries for Mizu from what Vergil could discern. But barring Mizu attempting to return it to him, he leaves the blade entirely in Mizu's hands.

"It's arguably more useful when a swordsman with a degree of earned confidence but too much ambition decides he must make defeating me an impossible goal of his."

It's a teasing taunt and in his typical fashion, Vergil doesn't draw too much attention to it, but there is a compliment embedded in his words.