^ This is the safe zone Res is talking about
Where the blue marker is on the map, is the closest safe zone to a Bolter feeding ground. It's less than a 10-15 foot walk from the safe zone.
Remember the Bolter gets frightened and will take off. Make sure your light is off and you're crouch walking towards it. One melee hit and it should be dead. Loot the Bolter for the tissue and run back to the safe zone. Sleep until morning, then sleep until it is night again and their should be another Bolter in its place.
Goodnight and goodluck!