After a morning to sleep on it:  Thoughts for the final episode
Walt is broken and has little strength yet.  That being said, sneaking up on the Nazi's is possible, as it doesn't take a ton of strength to shoot a machine gun.
But I just have a feeling that's the endgame that the writers want us to have, but not the endgame that is planned.
Walt knows:
1.  His money is irrelevant and gone
2.  His family is completely gone
What does he have left?  He's a notorious kingpin that has taken on legendary status.  The only thing he has left is his "empire". So I think he wants to cement that status.
In keeping with the line of the show, it wouldn't surprise me if somehow he ends up losing that status as well.  Somehow I think he publicly fails and the only thing he has left, his legacy, takes a hit.  What would be more crushing than the failure of Heisenburg.