Converting Bedroom to large bath ????

When I get finished with my bathroom remoldel that I am doing at the present. I want to convert a smaller bedroom 12 x 14 size to a nice bath. At the present time it has connected to it a small bath with a shower and all. Which I want to tear out and make a hall out of it. The reason for this is we can get to the new bathroom from master bedroom. And how the walk in shower and toliet I want to put in are all going to be on the oppisite wall which is a outside wall of the house. I was wanting to know if since I have a slap foundation can I go threw the outside wall and run drain pipes to my sewer or am I going to have to cut a hole in slab. I could raise the floor if needed in this area. I hope this is making since.