Qin Hai's decision to teach Xiao Nannan martial arts was not sudden—in fact, he had always wanted to do so, but never found the right opportunity.
Today happened to be a good chance, so Qin Hai called and asked Xiao Nannan to come over. Otherwise, he wouldn't have insisted on having her to keep him company in conversation, fully aware that she was so busy.
The room was small, but it was still sufficient for teaching some grappling techniques and simple moves. Both teacher and pupil were focused; one on teaching, the other on learning, and, before they knew it, the afternoon had quickly passed.
Qin Hai didn't hold anything back, sharing the combat techniques he had developed through years of actual combat experience with Xiao Nannan. How much she could learn was entirely dependent on her comprehension.