If you're going to leave the country then apply for the non b visa at a foreign embassy and come in with that for 90 days. Before the 90 days is up, apply for the one year extension.
You would be better off seeking advice from one of the Myanmar oriented Facebook visa pages, if there are any. Maybe you should be seeking political asylum.
If they decline then you get 7 days and game over.... ask at the counter first... before formally submitting your application... there is no bargaining, you're not buying shoes.