Can you play a card after moving to Zaun Warren but before its trigger forces you to discard?

Ruling: You can play Actions and Reactions during the Showdown that occurs after movement but before conquering. You cannot play Units at this timing.

Sequence:

• Merchant moves to empty Zaun Warren
• Merchant's movement effect draws a card
• Showdown begins on the open battlefield
• You gain Focus and can play Actions/Reactions during the Showdown
• You conquer Zaun Warren
• Zaun Warren's trigger to discard occurs

Nuances:

• Only Reactions and Actions can be played during the Showdown, not Units
• This allows you to play cards drawn from Merchant's effect before having to discard to Zaun Warren's trigger