Rise Donni

Donnie asked you if you could help with the experiment and you agreed.

Putting on your safety goggles, you commented that this thing was about to explode, and Donnie lowered the goggles over his eyes. He chuckled, "Dear, naive Narui, I assure you, if I do everything right, nothing will explode."

This continued until the experiment ended with an explosion. You both coughed, waving away the cloud of smoke. When it cleared, you looked at him again. Only it wasn't him. It was you. And you were him.

You somehow switched bodies.