I have a model where i need to make a lot of holes. The kind of the problem is in all of them the same. The position and size of the hole(s) is already set by a face and they should not change. So what i need to do is to punch the face through the part of the model to a backface. Here is an simplified illustration of the problem:
Update1: I don't have a separate mesh to make holes.
Update2: I have this problem probably more than 30 times in my mesh. So doing an extrusion, deleting backface, punching hole, recreating the backfaces, making the tunnel is unpythonic. Is there a shortcut for this?

