There's a secret entrance on the south end of the palace that leads to an escape tunnel. Just make sure the archers patrolling the battlements don't see you. There will be alarms, but you won't set them off. Richard will have to wait for you on the other side. Only those who have been spelled by Rahl's sorcerers can pass in and out of the barrier without being instantly killed by it.
The People's palace is surrounded by a tree line that acts as a magical barrier.
