Initiative Roll

Acting quickly is not a matter of skill... to do it you need to decide what to do, and do it... quickly.
Hence, the standard initiative roll is Agility + Smarts, .
Everyone involved in combat must make the same roll, and they act in order, from the biggest to the lowest roll result.
You can do this at the beginning of a combat, or you can do it once per round. Whatever suits you best.
Since one hit kills are feasible, scoring a high initiative is a great advantage.
Nonetheless, you may be doing things the wrong way if you are not ambushing ans sucker punching your way to the op of the food chain.