Reasoning behind that is plain training, all pilots know where her various 'oh shit' buttons are. It's part of the muscle memory.

IF countermeasures fail to spoof the missiles then you may shoot at them, but this will cost an attack.

IF the missile volly fired at you is four or more, the house rules cover this.

Entangle combat:
To escape its a straight 1d20 versus the defender and attacker.
In Dead Reign, latest combat rules; to escape an entangle is a dodge roll vs. entangler's roll (strike/entangle roll)

Holds:
To escape holds its 1d20+P.P. or P.S. to escape.

Attacking and Defending:
A natural roll of 1-4 auto misses unlike the book which only a natural 1 auto misses.
A natural roll of 12 or more is needed to hit with called shot unlike the book where attacker is allowed to use bonuses. In Dead reign; the latest combat rules its a straight roll; with penalties depending on target size. Its counts as two actions. You can make an Aimed called shot; with a +2 to strike bonus but counts as three actions.
You can add physical prowess bonus to firearm to strike roll unlike the book where you can not.
There is no -10 or -5 to dodge gunfire.
All ranged attacks require a roll of 8 to strike (including bonuses and penalties)
Firing through the cover of a completely covered opponent requires a called shot with a -5 penalty if you know they are there.

Mecha combat
In mecha/fighter combat; you can take up to three defensive actions. I assume these actions eat up your allotted actions per melee round.
1. Deploy chaff (automatic or no?)
2. If chaff fail; you can fire at missiles.
3. If the total number of missiles is 3 or less after firing you can now take a dodge action.

I think this 3 defensive actions is limited to missile combat.

More down the road when its comes up.