I can add this to the combat abilities section. Here is what I understand happens when a swift strike unit attacks an indestructible unit:
- Swift strike unit deals damage to the indestructible unit
- If the damage is enough to otherwise kill the indestructible unit, exhaust it and remove all damage and attachments (as defined in the rulings) and remove it from the patrol zone
- The indestructible unit hits back with whatever its attack is now (after losing attachments)
This means that if Oathkeeper (7/8 swift strike) attacks an Immortal with Spirit of the Panda (5+2/5+2 with Indestructible), the Immortal only hits back with 5 attack instead of 7, because it lost Spirit of the Panda to Swift Strike damage.
Does that sound correct?