It would have been more morally pure for Snowden to choose to stay home and face the consequences after his act of civil disobedience.
I don’t think it follows, however, that Snowden is acting irrationally or treasonously or (wrongly) “taking a hostage” by setting up (or claiming to set up) an information-disclosure insurance policy against reprisals by the US. For evidence for this proposition one need look no further than the very eloquent NYT op-ed by Nasser al-Awlaki, The Drone That Killed My Grandson. Remember that we now live in a country that has a track record of executing US citizens (so-called “targeted killing”) without trial, at least outside the US. The limiting principle, we are told, is that the US only does this when it considers them a grave threat, and cannot get hold of them any other way because they are beyond the reach of arrest — not principles likely to be of great comfort to a Snowden.
For a cryptographer’s analysis of this tactic, see Bruce Schneier’s, Snowden’s Dead Man’s Switch. Schneier suggests it may be counter-productive:
I’m not sure he’s thought this through, though. I would be more worried that someone would kill me in order to get the documents released than I would be that someone would kill me to prevent the documents from being released. Any real-world situation involves multiple adversaries, and it’s important to keep all of them in mind when designing a security system.
A commentator counters that in fact this creates a different incentive:
If the US does not want these secrets released then it is in their interests to keep him alive.
It’s also makes it more imperative to capture him in case anyone else kills him.