|Darksol the Painbringer|
We had this come up in a session last night against an invisible BBEG spellcaster, and I'm looking to see if there is something we're missing here, or if this really is just an ambiguous rule.
Our party Fighter, whom was Hasted, moved up to the BBEG Spellcaster with Flanking, activated Disruptive Stance, and used Improved Knockdown to debilitate, damage, and debuff the BBEG (since it was a Critical with a Fearsome weapon).
However, the BBEG had a Contingency in place to use Dimension Door if they got low enough health, which triggered after the Improved Knockdown took place.
Here's what Contingency says:
You prepare a spell that will trigger later. While casting contingency, you also cast another spell of 4th level or lower with a casting time of no more than 3 actions. This companion spell must be one that can affect you. You must make any decisions for the spell when you cast contingency, such as choosing a damage type for resist energy. During the casting, choose a trigger under which the spell will be cast, using the same restrictions as for the trigger of a Ready action. Once contingency is cast, you can cause the companion spell to come into effect as a reaction with that trigger. It affects only you, even if it would affect more creatures. If you define complicated conditions, as determined by the GM, the trigger might fail. If you cast contingency again, the newer casting supersedes the older.
Initially, the GM argued that because the spell coming into effect doesn't have any spellcasting traits or isn't an action of some sort that the BBEG could just use their Reaction and get away. However, I followed up by saying that, because the spell still has physical manifestations, and requires effort on the BBEG's part (hence represented by the reaction), that it would still require the components to function, which means it would still trigger. The GM eventually agreed, but disputed that because it would be a Verbal at-most, or a Concentrate trait effect, that only the Fighter in Disruptive Stance would be able to affect them.
Thankfully, this gives the BBEG the death knell, but I'm still wondering if we ran that situation incorrectly, or if there's some other information we're missing.