why didn't they call for backup? stupid , but i"ll go with it
hank said "I'll call in backup once we get on the road/get out of here" somethign like that. Letting the viewer know that no other cops were aware of their little operation.
They didn't want to put jesse in the system, as he'd lawyer up and get shanked in 3 minutes after Saul learned of his whereabouts.
They laid the groundwork for marie to celebrate, get the bad news (there is no way Hank survives this), then marie to MELT like we haven't seen before... then hank has to leave town, obviously. Walt will have to break the news to his family as he leaves town.
Really, I thought a guy as jaded as Hank... he might just take a few million cash $ and retire and just shrug off the heisenberg stuff. I know its been his hobby for so long, his passion, obsession... but the smart play... against a dude as evil as hank... was just to cash in, let him die, and keep that secret. I'm sure hank will remind him of that, as hank bleeds out.