If I am in a showdown state and use an action to kill the sole attacking unit my opponent controls, will my opponent have a chance to respond with an action before damage refreshes?

Ruling: Yes, showdown/combat continues normally even when one player has no units remaining. Both players can still play actions, and at the end of combat all units still heal.

Sequence:

• Combat does not end when one player loses all units
• Both players continue to have opportunities to play actions
• At the end of combat, all remaining units heal