Does a showdown end after both players pass once, or does playing a spell/ability reset the sequence, allowing the showdown to continue?

Ruling: A showdown continues as long as players take actions. The showdown only ends when both players pass in sequence without playing any spells or abilities.

Sequence:

• Player A takes an action (plays spell/ability) and passes
• Player B receives focus and takes an action, then passes
• Player A receives focus again and can take another action
• This continues until both players pass consecutively without taking actions

Nuances:

• You can use a reaction in response to an opponent's action even after you've already passed
• After a chain resolves and priority passes back to you, you can still use action spells
• At the start of a showdown, the attacker has priority