As soon as you wake up, run to the south end of the church and look for two sheds. Run to the farthest shed from you and enter it. After a while, guards will appear but not attack. After they will go back, open the door and kill one or two guards, then quickly run back into the shed and close the door. Guards will once again appear, but will not enter the room. They will go back again. Once again, open the door, and shoot. Keep returning to the shed for protection. Note: Keep checking the maps for incoming guards. If guards are approaching, do not go outside. Repeat this until all the guards that are coming for you are dead. Afterward, go back outside and kill other witnesses who are in the mission.