You cant flee anywhere nice, Snowden is trying to you and you see 99.9% of the world countries are willing to stuff their own constitutions and human rights treaties up their asses and stick their head in the sand at request of USA.
scnr
He rejected it for his own reasons.
I think it is a safe bet that they knew what Snowdens values were before making the offer and they fully expected him to turn it down. Or they knew it for certain...