So in the episode that most would consider the greatest episode, Season 2 E6 Teddy Perkins, we learn that Darius has a two-regret life limit pact. Not only that but he already has one regret. A regret so bad that if he has another one he would rather be killed than keep on living. I believe in this last episode we get a glimpse of what that could be. My assumption is that it would be spending more time with his brother who one can assume was very sick and later died. Though it was a dream sequence we get a glimpse into his personal family life. The conversation back and forth about staying and visiting and playing it off like it's cool to not wanna stay just seems like all conversations when someone has a terminal illness and the awkwardness of it all. Just speaking from losing a loved one also my regret is definitely not spending more time with them.