In drop 770, Q (talking to Snowden) said John Barlow was 187'd and that "you (Snowden) are now a liability". I'm sure Brennan and his ilk would prefer to not have him around any further to talk now that he is providing no further use to them.
Snowden is in danger now because he is a liability. When he runs out of shit to sell to Russia, he will be in real danger. Hope he makes the right decision.