Not long. [He briefly thinks back to his moment arrival.]

He had just thrown a sword at you and you caught it. It was then that I knew you had skill, hence why I didn't act sooner. If I unnecessarily interfered then I apologize, but I thought giving you an opportunity would have been better than just sitting idly by.

[Not that he was idle, but given that he didn't know for certain about the girl's skills nor how crazy this guy would be, he didn't want to take chances.]