Alrighty, so an incident came up yesterday in a game which we had some confusion over resolving due to wording. I will say it was a Cauldron deck which may be why the issue came up, since I don't recall this specific wording ever coming up in an official deck. I've done a fairly extensive bit of Googling to see if I can find an answer but haven't quite managed to resolve it.
So, what happened was that an environment card specified that all the current environment targets dealt damage to the hero with the highest hp, and we weren't sure whether to predetermine said hero and then deal all the damage to them, or whether the highest would keep being re-determined as the first hero stopped being the highest. We ended up playing it the first way since we were all low enough on hp that it was the difference between one hero being incapped and all of us being incapped (I mean, the other two were incapped shortly afterwards by something else, but anyway...).
The specific wording was "All Test Subjects deal the hero with the highest hp 1<type> damage". I can't remember the type but it doesn't matter for this issue. The nearest similarity with an official deck that I can find from my Googling is Siege Breaker, who hits the two highest and has them both determined before he deals said damage (though I'm not sure how they could change mid-damage unless hitting the first target causes another one to enter play which has more hp than the second target or something).
Thoughts?