If the airline can't move employees to where they're needed,Perhaps what they need are FAA mediators or someone who has the authority to give orders to airline personnel on the spot. They could have resolved the entire situation by simply ordering the four airline employees to wait for the next flight and telling the bozo "captain" to get stuffed. Problem solved, and that would have been the end of it.
there could be delays to passengers downstream. What
makes the most sense is to raise the offer to volunteers.