What is the word for hijacking something that was already just hijacked?

Suppose that, just after the hijacking of an aircraft, a third party (related to neither the initial hijackers, nor the pilots, nor law enforcement) forcibly took control of the plane for themselves.

What is the word for their action?

Is it a re-hijacking? Certainly not, because "hijacking" implies not only taking control of something you don't have a right to control, but also, in so doing, depriving the rightful controller of the same.

The US calls the act of hijacking a plane "air piracy," so I sought succor from old usages of "piracy." However I failed fo find any use of "piracy" to describe the act of a private party depriving pirates of a pirated vessel. If anything this was considered "privateering", a form of civilian bounty hunting targeted against pirates and hostile aliens (enemy ships at wartime).

However no such concept as "air privateering" seems to exist outside of steampunk and My Little Pony fan-fiction. Undoubtedly this nonexistence is contributed to both by the extraordinary difficulty of externally detecting planes victimized by air piracy and the near impossibility of subsequently boarding such a plane in order to commandeer it away from the hijackers. As well air privateering would seem a difficult profession to profitably maintain by boarding flights as a passenger in hopes of being presented with such an opportunity sheerly at random, not least of all because of ticket prices.

Despite it never having been called "air privateering," there is at least one historical example of an attempted "re-hijacking" of an aircraft by a party who just happened to be on board when the initial hijackers took hold. Their action however did not receive the moniker of "a hijacking" or a "re-hijacking" from anyone as far as I've been able to determine, despite the fact that their actions are believed to have immediately resulted in the plane crashing and killing everyone on board.

Some have called this "commandeering" or "attempted commandeering" rather than "hijacking" or "attempted hijacking" yet these subsequent takers of control did nothing substantially different during their attempt than the original hijackers. They also had no legal right over the aircraft and so, under US Code, they were no less "air pirates" than the first set of hijackers.

The reason these "commandeerers" are not called "hijackers" or "re-hijackers" seems to be due to the prevalent belief that their motive was different than that of the original hijackers, even though according to the law, their actions were equally illegal, and even though no one has been able to conclusively prove that their actions resulted in a less bad outcome than would have happened had they not decided to try to sieze control for themselves.

Further, the first hijackers tried to commandeer the aircraft just as hard as the second group tried to, yet no one ever calls what the first group did "commandeering" (it's only ever called "hijacking"). Yet the fact is that the first group succeeded at commandeering, while the second did not! So failing to commandeer something is commandeering, whereas succeeding to commandeer isn't?

I feel like there must be some proper word for this act of secondary hijacking/commandeering/piracy that eludes me. Please enlighten...

If I purposely kill someone, the crime committed is homicide, and I am a murderer. If I kill someone who is threatening my life and/or that of my family, the offence is called voluntary manslaughter even though I am, for all intents and purposes, the killer, I committed the unlawful act in self defence.

In the eyes of the law there is a clear difference between killing someone with malice and premeditation and without. The same principle applies to the situation described by the OP. If I am a passenger on board a hijacked aeroplane and I know for a fact that the hijackers are intent on killing everyone on board by using the aircraft as a weapon of destruction, I am justified in trying to regain control of said aeroplane. I am not the hijacker, I am someone trying to save my life and that of others on board with me.