I saw this come up on a FB post and couldn’t decipher the proper answer:
Model A has two actions, and it uses the first to Prepare and the second to move into range of Model B which has a Prepare token on it.
When Model B reacts to the move, can Model A then react to that reaction?!
RAW in the CRB reads that a model can “make a reaction in response to something an opposing model may do during one of their opponet’s turns” - does Model B’s reaction count as a
“turn” in this case?
Ooh, I love an edge case. 
My take on this is that the phrase “during one of their opponent’s turns” from top of P41 is superseded by the rules stated directly below, under the “Reactions” heading and also in the the rules on triggers (P42) which describe what qualifies as a trigger. In both places no mention is made of the trigger having to be on the opponent’s turn.
Because of this I view the first passage as an example or a non-exhaustive description (you could also make mileage out of the fact that it says they are “allowed” to act on the opponent’s turn but nothing written there makes that exclusive.)
The rules describing the trigger conditions are the most directly important to this question. In that passage there is no restriction on in whose turn the trigger condition can be met, so the actions described (Model A prepares then moves, Model B reacts, Model A reacts in turn) is fine.
It also makes for a fun/silly Princess Bride level game of double bluffing over who might do what in reaction to whom 
Finally, I can’t off the top of my head think why anyone would do this. Surely Model A is always better off moving with its first action, then making a second action (after Model B’s reaction) without the quick-action penalty (which could be to prepare at that stage, if they so chose. For this reason I don’t think it’s ever going to be something that we need to worry about, except for academic fun.
Hahahah Princess Bride - love the reference.
It’s a nit-picky one for sure, and I agree that ruling on the side of trigger conditions makes the most sense here. It’s the distinction of “turn” that caught my eye when I saw this on FB - I’d never noticed that wording in the CRB until now!
I also can’t figure out WHY the OP on facebook would want to make the moves in this order, but that’s the wasteland for ya!
It would not have any sense if a model can spend an action to get “Prepared”, and it cannot do anything in that moment being “Prepared”… so the model is Prepared, it sees a triggering action/quick action, and it could not do anything… just because it is only Prepared for opponent’s turn 
and not for the enemy’s action… that would be weird.
Hey gang,
A model cannot react to a reaction.
As @RyanDanger87 pointed out, page 41 of the main rulebook states that reactions are only a response to something that happens ‘during their opponent’s turn’. In the example they have given, Model A wouldn’t be able to react to Model B reacting to the earlier move because this does not take place during an opponent’s turn.
Unfortunately, the game of cat and mouse described by @Candyman would not occur. Whilst that section on page 42 does not have the qualifier of triggers needing to happen during an opponent’s turn, it is, however, mentioned on the prior page. The pages cannot be taken in insolation.
Essentially, in the simplest terms, you cannot react to a reaction as that react does not take place within an opponent’s turn.
We’ll clarify this come the next errata.
Thanks for clearing that up @Modiphius-Dom - much appreciated as always 
“Essentially, in the simplest terms, you cannot react to a reaction as that react does not take place within an opponent’s turn.”
What if there’s a Turret placed somwhere on the battlefield and it’s an enemy to everyone.
If My oponent Moves and the my model can see Turret shooting at him from its reaction - can i then React to that Reaction, since it’s all happening in my Opponent’s turn?
Or in case of any 1v1v1 scenario?
Hey @Lokee
They would not be able to react to that turret. Reactions do not trigger further reactions.
You could react to your opponent moving as normal.
In a three way scenario, you could react as I described earlier (although it is worth noting that the system is not built for multi player battles) - anything that triggers the reaction within an opponent’s turn but not a reaction itself.
Again, we’ll add this into the next errata pass.