Okay. You're free to think what you want, that was Koogi's intention with the last chapter, it's an open ending, you can make up your own interpretation. Personally, I think they're both dead.
When did Bum die??
Whaaaa? In the last chapter...as he was crossing the street, a car may or may not have hit him. I personally think he died on that crosswalk, fulfilling his promise to Sangwoo to be together in death.
When he was crossing the street running behind what he thought sangwoo .. if u reread it u will notice how the traffic light turn to red
I feel like Sangwoo isnt dead. Remember in the final chapter where Yoonbum was in the hospital asking the nurses for Sangwoo. I think the guy on the wheelchair with the iv drip, when Yoonbum was using the elevator, is Sangwoo. And the cops told that one male nurse to give Yoonbum some random person's fake ashes to get rid of him.