Master Protector Achievement
Get through a Gather with no damage and no one getting to the Little Sister.
This maybe be a little difficult until you find the right spot. While making your way through Ryan Amusements and enter "Journey to the Surface", you will have to harvest ADAM from a body in a open room. You can hack the turret and place Rivet Traps on the floor and around the doorways. Once you have everything setup, place the sister down to collect ADAM. You can now back up into the corner and pick off splicers as they flood the room.
As long as you watch out for any splicers with guns and let the turret do all the work you should earn this without any issues.