"I believe this thought, of the possibility of death - if calmly realised, and steadily faced would be one of the best possible tests as to our going to any scene of amusement being right or wrong." This suggests that accepting the reality of death helps us judge whether engaging in certain activities is truly appropriate or not.
"If the thought of sudden death acquires, for you, a special horror when imagined as happening in a theatre, then be very sure the theatre is harmful for you." The message emphasizes that avoiding situations that instill fear of death indicates those activities might be unsafe or unsuitable for us. The safest guideline is to avoid living in environments where we fear we cannot face death bravely."