So killing or sparing Bradley is a story line achievement!
However, here is what happens when you choose either option.
You are in the jail cell, someone will come visit you and speak with you, than go to sleep.
Eventually someone else will come visit.
Get thru this conversation than Bradley will show up.
Now if you decide to kill Bradley, this WILL effect your ending!!! So depending on which one your going for just be weary!
If you decide to kill him, he will hand you his gun and shoot him.
If you decide to spare him, than he will lay on the floor for you to escape.