so, here's a list of items you will need to escape successfully:

a rope
a knife
a wrench

as you can see, the window behind you is covered by a vent grille. use the wrench to either break it open or take the screws out.

in the event that a guard catches you trying to escape, use the knife to take out the guard. then, steal his gun just in case backup arrives.

if the swat team does arrives to serve backup, use the gun to kill the squad before they shoot you down.

use the rope to climb over the wall, be careful though as if you fall you might sustain an injury and never be able to escape again.

take the cop car and drive away from the prison. keep a low profile and try to act like a police officer driving the car to avoid suspicion or apprehension.