
The Fast keyword saves an action, playable in various player window, and ignores Attacks of Opportunity. For this expansion plus the Revised Core Set, all Survivor weapons can abruptly disappear from hand (Baseball Bat, Pitchfork, and Hatchet.) If the fight hasn't ended you may have to fight barehanded or with events, or have others take the heat while you re-setup. Two of those are 2 handed so you cannot setup an another sub-weapon to use when it disappear. So this seemingly lazy addition actually has some synergy going on. I was quite surprised at its ability to "upgrade" the original Baseball Bat and made me want to continue keeping that in the deck.
Many times I want to attack-pickup-attack with the Pitchfork to deal required damage but can't take any more AoO, if I play Fire Axe (2) in its place and finish the job then Pitchfork can be passed on to your friend. With Hatchet equipped Fire Axe (2) is also good to have ready on hand because you are not sure of enemy's HP and what it'll do with your Hatchet. If Fire Axe (2) is not yet in your hand, if you can get draws mid-fight like Overpower or Rabbit's Foot (or even Upkeep Draw while you still have enemies) it can come into play right away. In any cases where you are hiding Fire Axe (2) on hand, you are also ready to commit to anyone.
There is also a little in-box combo with Hunting Jacket where you may get the axe back after taking hits and you can immediately setup with it to fight back.
The action saved by Fast can be used with Double events in this box like Elaborate Distraction.