Ecuador's offer of asylum to Assange, and the fact that Snowden was traveling with a Wikileaks representative, is the likely reason for Ecuador being the originally chosen destination.
It may be ironic (for the US) and lucky (for Snowden) that he was in Russia when the passport was revoked. Likely one of the few places the US may hesitate kidnapping him from. From a kidnap / rendition viewpoint, Ecuador is just one country on a long list of countries to which the US would probably not hesitate 'arranging a small excursion'.
At the time and date that he likely came to that regrettable conclusion, he found himself in one of the few places in the world where the US cannot arbitrarily rendition someone from without significant risk and possible consequences.
The passport revocation means nothing, he had nowhere else he could possibly go without high likelihood of rendition even if he had a valid passport or wanted to leave Russia.