From a man's point of view, this coach may have a good impression on you and want to make friends with you. The deeper meaning may be that you attracted him in some way. But he doesn't know you, but he is still attracted to you, so he can only take the initiative to chat up and get to know you. But it can be seen that he may be a relatively introverted person. He will take the initiative to summon up courage, be responded by your frightened expression, and be exposed by others, and he will not be able to face it. Maybe he doesn't hate you, but it affects him. Maybe he doesn't know how to face you. Introverted coaches have this problem when they meet a simple girl like you. Don't think too much, just let nature take its course. The purpose of going to the gym is to exercise and make more friends. But whether it's making friends or fitness, safety is the first and caution is the best. You did the right thing. So don't worry.