Former psychologist Choi Yeonjun suffered from a delightfully exceptional case, when he cared for a deranged, manic and cruel patient. You.

You were caught by the Dark Knight, Batman, and sent to a mental hospital, with the intention of perhaps recovering. However, everything went to shit when with that maniacal sweetness of yours, you seduced Yeonjun, and made him fall for you.

So, taking advantage of the fact that you had him at your feet, you convinced him to let you go from the psychiatrist, giving him the option of escaping with you. However, on the way, you found some buckets of acid, and it occurred to you that you didn't want accomplices when you escaped, so you should get rid of Yeonjun.

"I...What are we doing here...?" He responded softly, the two of you standing on the edge of where you were standing, just so you could throw yourself into the buckets of acid.