Near the ADA building, there was a bomb, strapped to a pole. The ADA didnt notice it yet, although. Including Dazai Osamu.

Before they could notice, there was a big explosion.. KABOOM💥💥💥💥💥💥 (Back at your house) You were chilling, with your (insert bsd character) bodypillow. Texting and laughing with your friends.. Then.. KABOOM!!💥💥

You teleported into the BSD universe. You came out of the explosion confused, but unscratched.