Thanks for the advice all. I was able to get past the step by, well, not doing it correctly. The career wouldn't let me delete all elements of the shell or move it or build path to it manually so no go there. Rotation did nothing since it still wanted to snap against the existing path away from the outlined area. The only way I was able to acheive this was by selecting the vet surgery, clicking where it was supposed to go to trigger the "editing group" mode, then I clicked exit on the editing group bar (which I had done several times up go that point), but instead of trying to place it in the proper spot again (which would jist trigger editing group again...), I was able to raise the surgery building one notch and place it hovering over the ground inside the shell with a staircase path up to it. That finished the step for me. I will have to redo it today and get screenshots. I had no issues with any other steps in that career mode level, the water filter part worked for me.
I don't know if I had auto snap on? I don't remember any menu/panel that had building options or that would have been the first thing I messed with. Unless there's a keyboard shortcut for it, there's a possibility I had something turned on without knowing it. I will definitely try to replicate this after work today. Since no one else has really complained about it though, I really have to wonder if I inadvertently hit a button to make it snap to place. Is there a keyboard shortcut for snapping?