Isn't it insane Bodhidharma cut his own eyelids?

I am not questioning the path of Zen. It just exist as it is. But I read this legend about Bodhidharma. To stay awake he cut off his eyelids and tea was flourished. Upto now I have felt tranquility in meditation. But isn't it an insane act. How people tell this story about a great Zen master? Or is it mystical way of delivering something which I am not understanding?