Jayden is analyzing the clues surrounding Shaun's disappearance. After he's done, his nose will begin to bleed and he'll have the urge to get high. Resist. Follow the QTE's. The easiest way to do this is get Jayden to the shower. Go into the bathroom and turn right. The shower is around the corner.
Note: If you were arrested in Fugitive, then this scene won't be available to you. You have to escape into the subway.
Replay Chapter: Jayden Blues