And how do you intend to have infinite ways to discard Emery?
Look at the text of the spoiled Leadership event behind Merry in the picture... it's possible that is says all allies who leave play go back to your hand instead of to the discard pile. So you can trigger Emery's action to put her back into play, discard the cards, have her go back into your hand, then do the action again until your deck is completely discarded.
So I'm hoping the hidden text on that event limits the effect in some way.