Magic: The Gathering Sorcery vs Activated Abilities

Question

The question I have is for a hypothetical situation where even though rules state(if I read correctly) that activated abilities are in their own unique stack to their owner. Player A plays a field wipe card like say Whelming Wave or Evacuation—can player B tap their creatures in response to the target player to deal damage and kill them before either card resolves? Or, is it simultaneous or does the wipe go off?

I'm relatively new, so I'm curious. The opposing player can really go "In response to that" and make it meaningless? It's fine if it's a rule, but it defeats the purpose of strategic play, of disabling such things because they didn't do it first. If it's considered on top like a counter to my card, it makes sense, but if the stack is supposed to be unique, outside, not on top of an already resolving card, then I'm not sure what to think by the way it reads.

Answer 1

There is one stack, that all spells and abilities use (with the exception of special actions and mana abilities). In your specific example, player A casts Whelming Wave, and once they finish casting it, it's on the stack. Then, player B activates their creature's ability "in response" to the Whelming Wave, meaning "while the Whelming Wave is on the stack". That ability goes on the stack on top of the Whelming Wave. Then the ability resolves, and the ability does whatever it does. Finally, the Whelming Wave resolves, and, the creatures are returned to their owners' hands. If, however, the resolving ability killed player A, the Whelming Wave would immediately leave the game with its controller, and it would never resolve.

This can happen because abilities can be activated at instant speed; in this case, they can be activated in response to other spells or abilities. Rule 112.3b says

Activated abilities have a cost and an effect. They are written as “[Cost]: [Effect.] [Activation instructions (if any).]” A player may activate such an ability whenever he or she has priority. Doing so puts it on the stack, where it remains until it’s countered, it resolves, or it otherwise leaves the stack. See rule 602, “Activating Activated Abilities.”

Notable exceptions are the Equip and Outlast abilities, which can only be activated at sorcery speed.

Answer 2

The question I have is for a hypothetical situation where even though rules state(if I read correctly) that activated abilities are in their own unique stack to their owner. Player A plays a field wipe card like say Whelming Wave or Evacuation—can player B tap their creatures in response to the target player to deal damage and kill them before either card resolves? Or, is it simultaneous or does the wipe go off?

No If a player looses the game all his permanents are exiled and none of his spells that may still be on the stack resolves. I don't know if it can really matter in 1v1 games but in multiplayer games it does matter and the multiplayer parts of the rules gives the following information.

800.4. Unlike two-player games, multiplayer games can continue after one or more players have left the game.

800.4a When a player leaves the game, all objects (see rule 109) owned by that player leave the game and any effects which give that player control of any objects or players end. Then, if that player controlled any objects on the stack not represented by cards, those objects cease to exist. Then, if there are any objects still controlled by that player, those objects are exiled. This is not a state-based action. It happens as soon as the player leaves the game. If the player who left the game had priority at the time he or she left, priority passes to the next player in turn order who’s still in the game.