Do you think this means/implies that the action can be used out of sequence (i.e. you don't have to wait until you turn in the initiative order) or even in fact that it doesn't count as an action (i.e. use up your turn) for that round?
The effect text on many of the cards use the term immediately, in response to some other condition that the reaction card is supposed to alleviate. i.e. when X happens you may immediately do Y to lessen/prevent the impact of X.
how are people using these cards with the initiative track?