Exactly, he is an idiot if he comes here now. They will lock him in Quantico pending Kangaroo FISA secret trial with a predetermined outcome.
He needs to just relax until a sane British government or US Government lets him walk. Either that, carefully work on a solid escape plan, execute it, and get to safety in Russia before they know he is missing.
He is in a good position to do it if he carefully plans it.
At the very least he should wait until Trump has been in office for a couple of years and see how the swamp draining is going. A better bet would be to wait until Trump wins re-election in 2020.