The blast doors...? [spoilers]
I didn't see how or where Bond reopened the blast doors, which when closed, they said, would cause the missiles to bounce off. Did I miss it?
Regarding Bond's demise, Craig's portrayal begins with Bond's first kills & promotion to 00 status. So no reference whatever to the previous incarnations. So why not close out his portrayal this way?
Maybe he feared doing a Sean Connery & returning for another go.
I don't think the series, if it does indeed continue, will have any believability issues recasting Bond for a new set of adventures.