Simple question: can an active model declare Discover + Discover against the same marker (say, for example, a camo marker)? The question arises from the rule that a model who fails to discover a marker may not attempt to do so again in that same player turn, however, my interpretation is that both rolls would be simultaneous, and thus one would not take place before another.
All actions of a single order are conclused simultaneously, therefore you are right. Therefore there can be no failed discover roll if you both make it at the same time.
You're right but your wording implies more than it should. At resolution there is no failed roll, so both rolls are legal. In effects, it's possible that one (or both) of the rolls will fail and this may have consequences. The reason this may be important is in the case of Impersonators. It's an open question whether you would be able to attempt to discover the Impersonator again in the situation where you declared Discover + Discover vs an IMM-1 marker and succeed at one roll while failing the other.
No, it's not open. IMP-2 marker (after the first Discover-Discover ended with 1 good + 1 bad roll) is a different marker from the IMP-1 that it was before.
But it's the same Impersonator. The Impersonation state says that a failed WIP roll prevents you from Discovering that Impersonator again. Both the IMP-1 and IMP-2 marker are the same Impersonator, so I see no reason why that wouldn't prevent you from declaring Discover vs the IMP-2 marker in subsequent orders. However, @Mahtamori makes several good points in recent conversations. So I no longer know how it's supposed to be played. Which is why I think it's an open question.
to keep it simple (emphasis added): http://infinitythewiki.com/en/Discover A trooper that fails a WIP Roll to Discover a Marker cannot attempt to Discover the same Marker until the next Player Turn. Since IMP2 is a differnt marker, well this passage allows for another discover. http://infinitythewiki.com/en/Impersonation-1 If an enemy fails his Discover Roll, that enemy cannot attempt to Discover the same impersonator until the next (Active or Reactive) Turn. Since the impersonater is represented by different markers...well...no further discover allowed Both passages support different interpretations. Discussion has been going on for quite some time, there are good arguments for both sides. I guess that these rules are wirtten with only one discover roll in mind.