I'm really uncomfortable with the "held Actions". In most of other games, it is something you can easily get through, for, usually, it is quite useless and inadapted.
It seems very different in Hero.
So let's talk about that :
Mad Scientist has Dex 13 (17), SPD 3 and Fast-Draw 17 (thanks the coat).
In front of him is a cow boy with Dex 18, SPD 4 and Fast-Draw 15.
It's a classic pistol duel at Hgh Noon.
The Cow-boy should fire first, but if he does it, he would be charged with murder (even if such a situation can look quite weird for any lawyer). So, he hold on, but in the same phase, because that foght start on the 12th segment (the beginning of any fight).
On Dex 17, Mad Scientist may fire. But then, he has to draw his gun fast, so he can fire in this segment. Cow-Boy shall also do this, seeing that Mad Scientist is going to shoot.
he makes a fast draw roll, success is 5. Cow-boy's marge of succes is only 3. But he has the best dex, so he shout the poor mad scientist...
Then, you don't need a high Fast Draw score, but a high dex.