When an Add ability is activated in this way, it immediately finalizes and resolves, even during the resolution of spells and abilities.
§ 429.3.a Core Rules PDF (officieel)
§ 429 Add
§ 429.3 Activated abilities that Add resources and have the Reaction tag can be activated at any time that spells or abilities require resources be paid. Example: A player can add Energy and Power through any means before initiating the process of playing a spell. After initiating that process, in the Pay C…
