He went to the UK, but strictly speaking isn't in the country - he's in the Equadorian embassy, and doesn't leave it.
Edit: if you're inclined to disagree, please point out any factual inaccuracies or weaknesses in my reasoning rather than reflexively reaching for the down vote button. Assange entered the UK in late September 2010 and the arrest warrant became valid in the UK in December. That's a lot of time to book a flight elsewhere. The Ecuadorean embassy was a last-ditch move when his appeals failed.
More generally, the "weakness in [your] reasoning" is partly the arrogance to imagine that you understand Assange's legal options better than his lawyers did. But it is also partly the logical fallacy of ad hominem rhetoric, since you accuse him of hypocrisy and then use that accusation to try to discredit concerns of his that very clearly have nothing to do with questions of personal character.
As other commenters on this thread have mentioned, and as minimal research will confirm, Sweden has a long history of illegal rendition. Its handling of this case is extremely unorthodox, politically motivated, and shows a fairly clear attempt to maneuver Assange into indefinite detention through a legal process that even the UK High Court commented on as being unreasonable.