To tell ya the truth, I don't know what happens in the currency markets either.
I know that if that happens when trading the e-mini's (it can, has and probablly will happen again in the future), you start praying, not that that will do any good.
In general, you want minimum leverage when putting on trades, it gives you peace of mind and assures your longevity in this game.
From what I hear, the FX markets can be pretty treacherous waters for little fish, so to get specific knowledge on trading the FX markets, look-up Electirc Savant, he has his own thread, called The Perfect Edge and you can also do a search on his ET name and become very knowledgeable about trading the FX markets without the prerequisite ass-kicking that the markets usually hands to a trader in return for getting your skillz up to par.
Best Regards,
Jimmy