You have to have fulfilled the mission objectives so it is asking you to exit first
This trophy is for using an exit you can only access if you’re holding the paddle for the raft. It’s on the wall of the garage in the Schmidt house which you will already have access to if you did the real estate/house showing story. If not, you can get a spare key on the right of the front door in a flower pot.
Paddle in hand, run down to the creek at the bottom of the map and there will be a new exit next to the water. Take it and 47 will slowly make his escape.