Poison between turns

[mudkipmaster]

player A is battling player B

It's very late into the game both player A and player B's active pokemon are poisoned and have 10 HP remaining after player A does they're turn they decide that they cannot switch out ther're pokemon. So player A ends their turn. Question: Which pokemon would be knocked out first? (Our ruling was that since player A ended their turn, they would resolve all of their inbetween turn effects before player B. Is this correct?)

 

[PokePop]

No, it's not.
Both players' Pokemon are KO'd at the same time. There may be an order to who draws a prize first, but that's just needed to keep things orderly. The player whose turn is about to begin will replace their Pokemon first and the player that just ended their turn will draw their prize first.
But in game terms, the KO's are simultaneous.