Question on Boring after Drilling Operation

So we are CNC machining a part that has a similar shape to a 2 Liter Soda bottle cap. But its in 316L stainless. The part requires the rear of the ID wall to be flat. So lets say I decide not to use a flat bottom endmill. I want to use a standard drill. The particular drill we are using is a .562″ diamter carbide drill with 140 deg tip angle. Now after this drill I want to clean up the ID as well as create the flat surface on the rear wall. However, I’m left with an 70 degree angle (per side) against the rear wall and my boring bar has almost no relief angle on it. So machining direction from ID to centerline is not really wise. Can I machine it in the opposite direction from centerline, to ID, back out to Z0.0 ??? or is there a better way to do this ???