Very, very unlikely. Even though employment laws are very employer-friendly in the US, from the sound of it, Tom built an inclusive, open company culture. One of the side effects of that is that if you abuse your power as a leader, you cause irreparable damage to the culture - which is not something you want to do at practically any cost after spending so much effort building the culture and getting it to stand up on its own feet.
Ricardo Semler, major shareholder and CEO of Semco, explained it like this: "I have a handgun in my desk drawer with a single bullet in it."
If he really had built the kind of culture where he could just fire people by snapping his fingers, surely the easiest thing would have been to fire the troublemaker at the first sign of trouble instead of waiting for her to resign and make a fuss.