Did Lu Xiao die?
Before I go on, I want to clarify I am well aware there is no right or wrong answer. Even after I went through all the reasons why no or why yes, there is always something that turns it around.
These are reasons to believe he did not :
1. When Nan Chu asks Lu Xiao to promise he will meet her after she is rescued from the forest fire he does. When they reunited in that last kiss of the drama he told her he would always keep his promise. When he had to go back into the forest, she told him she would wait for him at home. His response is that she should wait for him. I take this as his promise that he will meet her at home.
2. Some are thrown into the death camp because of the 4 friends eating dumplings. Two of them have already died. Some assume the ML is dead with them. But take a look at the final scene. Yang who was one of the four is also sitting in the audience with the rest of the firefighters so the double scene cannot be used to support the death premise.
3. The scene where Lu Xiao enters the theatre shows him sitting at #34. The director again going for creativity. The number 3 in Chinese is associated with life or birth and is usually considered to be a lucky number. The number 4 is si in Chinese which is associated with the word for death. Life and death. He sits on both. I am still thinking about this, but death is still not conclusive or maybe I am just overthinking this.
Another purpose of showing the seat number is to indicate that he did not sit in the empty seat that was reserved for him. The seat that was reserved for him is #1. It could be he arrived late and came in through one of the side back doors in the top right corner of the theatre. It was completely empty in the back and gave the appearance that he entered an empty theater.
4. As Nan Chu looks out at the audience, she sees Lu Xiao watching her performance she smiles and says, " You go protect the country. I will protect you." This is reminiscent of her actions earlier on in the show when she released the video that would free Lu Xiao from any responsibility for a fire caused by that old actor(forgot his name). She knew it would be detrimental to her job and would bring problems for her but she told Lu Xioa that he protects the country and she will protect him. When she went away to the US, it was to protect him. This theme recurs throughout the drama and the drama ends with it. To me, he is not dead. He is away protecting the country.
Feel free to add your thoughts in the comments below.