Heavy speculation here, I’m just theorizing hard right now but the reason I think it might be possible, is that Valor doesn’t necessarily have to be powerful enough to intervene against Retribution, if Valor laid claim on Dalinar’s soul, then that would be considered an Oath, a contract maybe, that the Honor within Retribution would have to respect, that’s why I think the power within Taravangian was telling him “He’s been claimed by another”. Because remember, someone holding two Shards doesn’t necessarily mean they are “combined” both intents of Honor and Odium are in there.
Another reason I think it might be possible, again HEAVY theorizing here I’m just playing with, but Valor has remained ridiculously hidden from others, how is this possible?
What is the one place that not even Shards can see into? The Beyond.
Maybe Valor is riding somewhere between life and The Beyond, or inside it somehow? So perhaps during the stretching that Retribution observed, Valor could have snagged Dalinar along the way?
It’s been stated that Valor is a dragon, and they seem to have their own set of rules or things they can do different than other magics in The Cosmere, like the “Meditative Realm of The Dragons” that Hoid reached into using that bone he pulled out at the end, stating “There he sought the wisdom of the ancient dead, who could see far more clearly if you knew how to get them to talk to you.”
Maybe the realms are somehow connected? Or closely related, I’m really just throwing spaghetti at the wall and seeing with sticks.
Yeah there’s still so much we don’t know, those visions are a very big mystery still.