THEORY TIME!!!! So what I'm assuming is Sujin probably is the actual cause of the explosion in Boston. From what it looks like from all the memories that we've gotten so far are saying is Kang Hyeok was cheating on Ha ran with Sujin. Chan came clean about chatting with Ha Ran so Sujin found out and Spazzed causing the reagent to spill. Chan got the news Ha Ran was coming tried to tell Kang Hyeok but lab went BOOM!!! Sujin lives Scott free but is salty at Chan since he lived and even more pissed since he's in a relationship with Ha Ran. Chan needs the info Sujin has to regain all his memories to Tell Ha Ran the truth but Sujin Not tryna hear any of that and if she wants, could spin the story any way she wants since Chan's memories aren't complete. I have 2 episodes to see if I was cooking or not lol