This is all kind of stupid. If someobody points a gun at you, all you need is that thing Jackie Chan did in Rush Hour, which you can learn from watching the movie. I've done it in real life. If there's more than one person, you can't do anything.
Because of this, you don't need to pick and choose which style you learn, because the only situation it will be useful in is against a single opponent, in which case nearly any discipline will defeat someone who is undisciplined. Therefore, what you need to be asking is which martial art looks the best. You must learn Drunken Boxing. I've been studying it for six years and never lost a fight, even though suckers will tell you it's not a very good style.