For those who may not understand, here's what I could understand (note that this is just what I'm pretty sure happened, not what actually did)
While aaron was trying to take out the bullet, Kyungjoon's soul started to detach from his body.
So, in Kain's conscious or subconscious, Kyungjoon started to deteriorate. (Or maybe he was just going back to the real world, idk)
So that's why Kain went after him.
Before they made it to the real world, Aaron wasnt done taking the bullet out.
When they got to the real world, even when the bullet was only halfway out, cain started getting back his power very quickly.
Doing this did something to the bullet (idk what) and that's why Aaron and Gaile (idk if I spelled his name right) started running
*Again remember that this is what I THINK happened, please correct me if I was wrong ^v^
UPLOADERYANEEDTOCHARGEYADANGPHONEIT'SAT3MFPERCENT
Right!! Lol
THEY FORGOT TO CHARGE THERE PHONE I GUESS- SINCE IT'S 9AM