Mechadendrites with weapon profiles can be used to attack as a reaction - does this attack occur before or after the triggering action? If I say 'attack any target that attacks me in melee', then does the mechadendrite attack occur before or after I receive the melee attack?

EDIT: Sorry, I misunderstood the question. My real answer:

You seem to be able to use a Reaction, which can only be done during another person's turn. The advantage of this is they can not dodge or parry the attack, since its a reaction, and its their turn, so they can't use a reaction to react to a reaction. I hope that makes sense. So you would laser an enemy during their turn, and if you hit, it would be unavoidable (except by power shield).

Alternatively, you can assume that the writers meant to say that you can spend your reaction to make a standard attack with the mechadendrite as a free action during your turn. I feel this was their intention.

So can an attack made by a mechadendrite be evaded if the attack comes on the defenders turn?

(side note, I'm saying this because I absolutely hate how they've worded this part of the rules, its uselessly complex for so little gain)

So can an attack made by a mechadendrite be evaded if the attack comes on the defenders turn?

(side note, I'm saying this because I absolutely hate how they've worded this part of the rules, its uselessly complex for so little gain)

I answered your question in an edit to my response. In short, per RAW, no, they couldn't evade the shot.

It's an especially important question for melee mechadendrites when the enemy begins their turn further away from you. When an enemy is closing in, it's pretty important to know who has the "right of way".

It's an especially important question for melee mechadendrites when the enemy begins their turn further away from you. When an enemy is closing in, it's pretty important to know who has the "right of way".

Are there any Reaction actions that do not interrupt or change the triggering action? e.g. both parry and dodge are (using DnD 4e terminology) Immediate Interrupts. Their effect occurs before the trigger effect, which may nullify the effect.