Question about Mistbound: Discarding is forced

A question about the card mistbound in the Nightmist deck.

One of our players just used Mistbound to lock down the villain deck, discarding cards and all so the effect took place. Now she’s forced by the environment to play another Mistbound. She still has enough cards in hand to accomodate the discard requirement, but is she forced to do so? Can she opt out and just discard the mistbound without triggering the effect?

I think she has to discard because the card doesn’t say “may”, but I’m not sure. I think the card requirement is so that you cannot play it as the last cad in your hand, discard nothing and then still get the benefits.

Thanks in advance for any pointers.

Regards,

It doesn't have a may on the discards so yes.   If you can't discard a total of two cards the rest of the text doesn't happen.  

Pretty much as you said it.

You have to discard to get the benefit and you have to discard when it is played, there is no choice (as on Haka's Ground Pound for example).

Thanks for the input, much appreciated.