INJURED BUT STILL HERE: STOP. Emma Frost can use Invulnerability.

So the STOP means it can't be countered or ignored. Does this mean that Emma can't be pulse waved through her invulnerability when on this click?

That is what it means, yes.

Please do note that if a characters hits with an attack that makes it so you can't use Special powers or defense powers in this case, you'll blow through the stop click since they can't use it.