Now that we have Red Velvet's Peek-a-boo as a clue given by SM themselves we can say that Jonghyun was trying to reach out for help but the line was cut by SM as depicted here (plus another interesting point on the Werther effect!) :
뮤비 피카부의 마지막 장면에서도 위험을 직감한 피자집 청년이 도움을 요청하며 다급하게 전화를 거는 공중전화 부스 한쪽에 또 다른 많은 실종자들(희생자들)의 사진이 담겨진 전단이 붙어 있는 것을 확인할 수 있다. 이 장면이 대스타 한 사람의 죽음이 가져올 베르테르 효과를 예측한 것인가?
In the last scene of "Peek-a-boo", the pizza boy who is now aware of the danger tries to call for help. On the side of the public telephone booth we can see a flyer with pictures of other missing persons/victims. Is this scene predicting the Werther effect (A spike of emulation suicides after a widely publicized suicide) that this star will bring?