For this you need Acrobatics level 1, after you have been "Recruited" by the Monastery all you have got to do is head over the Arena.

You will see part of the wall is barred, but not all of it, now all you have got to do is jump over the wall and since you have Acrobatics you will hit the ground and roll, so you should not take much damage.

So you're home free! Make sure you have full life, just in case.