The important bit to remember is that yes, as usual, you can put spells/effects on the stack at any time even after spells have started to be resolved, as long as said spells/effects can be cast at “instant speed”, not “sorcery speed”.

Can you activate abilities during end phase?

Ending phase This is the last chance players have to cast instants or activate abilities this turn. If there are no triggered abilities put onto the stack during the cleanup step, no player receives priority during the cleanup step, so no spells can be cast and no activated abilities can be activated.

Can you respond to the stack resolving?

Since the stack resolves in order from top to bottom, those spells and abilities will resolve before the spell they were played “in response” to. Actions that do not use the stack, such as paying costs, playing mana abilities, or turning a face-down creature with morph face-up, cannot be responded to.

Can you cast an instant in response to an activated ability?

Activated abilities and instants can both be used/cast whenever a player has priority.

When does activating an ability put it on the stack?

Rule 112 covers this adequately. Rule 112.3a tells us that Activating an ability puts it on the stack, until it resolves, is countered ( Stifle ), or it otherwise leaves the stack ( Time Stop ).

What happens when an ability is removed from the stack?

The ability becomes the topmost object on the stack. It has the text of the ability that created it, and no other characteristics. It remains on the stack until it’s countered, it resolves, a rule causes it to be removed from the stack, or an effect moves it elsewhere.

When do you activate an ability in RuneScape?

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.”

What are the rules for activating activated abilities?

See rule 602, “Activating Activated Abilities.” 112.7a Once activated or triggered, an ability exists on the stack independently of its source. Destruction or removal of the source after that time won’t affect the ability. It is possible that they are confusing this with the rules regarding tracking objects that are moving between zones.