Besides having an effect that is actually pretty good on its own, this card makes Dynamite Blast much better. It can be used to perfectly position the enemies and keep the investigators out of the blast radius. In some situations it is better than Elusive as a dynamite-enabler, since it can avoid putting your teammates at risk, and because it can move enemies into a location that has other enemies, to group them together. And unlike Elusive, warning shot is in-faction so all who can use the dynamite can use it. The firearm ammo requirement is definitely a limiting factor, since many decks include few or no firearms. But now with .45 Thompson, there are a few options to choose from. It’s also worth noting that it cannot move elite enemies.
As an additional cost to play Warning Shot, spend 1 ammo from a Firearm asset you control.
Move all non-Elite enemies at your location to a connecting location. This action does not provoke attacks of opportunity.
If you don’t actually need to defeat enemies as a guardian, this opens up a lot of opportunities. Roland and boxing gloves Nathaniel only benefit from the first foe they beat a round. Zoey, Mark, and other people with access to this card but don’t have evidence in their hand...this is a testless, room wide evade. Sending someone to an empty room is the equivalent to a defeat if the enemy isn’t a hunter. Unfortunately, unless you can recover events, you only get two attempts at this on your deck... but for Zoey, it means you can farm the same enemies for engagement, getting paid each time.
If you have a particularly rough enemy you can’t defeat in two attacks, but have a nearby investigator who hasn’t attacked...Send them over.