Like friend Stephen Camp, I'm not a fan of the PRC, but this undercover police officer there did exactly the right thing when assigned to deal with a hostage-taker who had already stabbed his victim. She waited until he was distracted, and shot him in the central nervous system, repeatedly. (Video with English captions here.)
Some may try to make an issue of the smile and relieved chuckle that she gives to the surprisingly aggressive* interviewer's question about being nervous.
But she had won a fight, rescued an injured and endangered hostage, and had not gotten hurt herself. Moreover, she comported herself well throughout. Hell, she even had rounds left over.
When you win a fight, it's okay to give a relieved smile.
*They ran up behind her to video over her shoulder as she fired the last rounds. You think American news crews would be so bold, on average? And would they get that kind of access? State-run news, people.