IMHO, sounds like this person scares you and others. Perhaps you need to look at your own fears about training and why you took up a martial art.
Then, just politely say, "No thank you," and train with some one else. Its a preference not a problem who you personaly choose to train with.
I am surprised you Sensei has not corrected the situation. My Sensei has asked people (one) to leave because of an unacceptable injury rate.