I recently played against Vader in a Lambda. My opponent played it in such a way that he claimed he could use Vaders choke after any ship performed an attack. Having re-read the card it does say after an attack on an enemy ship you may suffer two damage to cause a critical hit.
I always thought that it had to be the Lambda that performs an attack and this certainly seems (IMO) that it is the intent of the card.
Any help here would be appreciated! Before I'm starved of oxygen!!!