He is threatening to reveal more secrets. If it is determined that he HAS secrets that put our country at risk, wouldn’t it be proper for our government to treat him as an enemy combatant, and certainly killing him would prevent him from releasing harmful information.
It would certainly be smarter for him to keep his mouth shut about future intentions to betray his country.
I'm not especially rooting for this guy -- I don't see any "good guys" on either side of this equation. But to put such trust in agencies like the NSA, when their mission has been subverted and who are actively working against the American people, is unwise at best.