Honestly we all know yinsen wanted to die to be with his family. It would be so easy for him to kill himself with all the equipment they had available or to just provoke a terrorist into killing him. Instead, he chooses to save the guy that was probably, no matter how remotely, complicit in his family’s death. But he saves tony. He chooses to live only to make sure tony makes it out alive. Yinsen is a hero, and his lasts words were to tell tony stark not to waste his life.