Can you activate runes to add Energy while resolving Bullet Time, even though Bullet Time only requires Power to be paid?

Ruling: Yes, you can activate runes to add any resources (including Energy) while resolving Bullet Time, as long as there is any cost to be paid during resolution.

Nuances:

• Rule 416.3 allows activated abilities with the Reaction tag that add resources to be activated during resolution of spells that require resources to be paid
• The rule does not restrict you to only generating the specific type or number of resources needed
• You can float resources even if you don't intend to use them immediately