Lee Min Ho's stopped heart started to beat again thanks to Kim Hee Sun's tears. 

On the Monday episode of SBS Mon/Tues drama "Great Doctor," Choi Young, played by Lee Min Ho, is saved by Yoo Eun Soo, played by Kim Hee Sun, from the brink of death. He had lost consciousness because his wound became infected and Yoo Eun Soo had been trying to save him but he didn't have much will to go on living. 

She told Jang Bin, played by Philip Lee, "No matter what a doctor does, if the patient himself has no will to live, it's useless."

Choi Young's heart ultimately stopped and though Yoo Eun Soo tried manual CPR, it wasn't enough to save Choi Young without the proper medical equipment. 

Jang Bin tried to stop her, but she didn't give up. She cried, "You said you'd protect me!" and continued her resuscitation efforts and when her tear hit his cheek, his heart started to beat again. 

In this episode, Yoo Eun Soo was seen yelling right back at Ki Chul, played by Yoo Oh Sung, who was talking rudely to her.