How can one get promoted to CPT outside of the board, specifically in deployed environment?

Honestly, I do not know of a method other than a battlefield promotion. Regrettably I am not sure this has been done since WWII. At issue we have a peacetime Army fighting a war. A very peculiar thing. I have been told that if you obtain an SF Officer's qualification and are a truly outstanding candidate, you have a good chance of selection for CPT "below the zone" (usually 1 year early). But you will still require consideration by the board and it is very uncommon.