On site 4 there is is a group of red gerbils to your right, for this achievement you are required to not touch these gerbils, with your bombs or the gerbils.
As hitting the red gerbils fails the level this is unmissable while going through the story.
I placed 2 bombs for this level, one to the right of the pyramid and one to the right of the second gerbil on the right.
Here's a video.. it wasnt easy, place the bombs closer to the gerbils than i did, was hard to juggle 2 phones.