The notion of counting on getting arrested and getting sued are just good defaults to consider just like counting on having to fire your gun if you are in a dangerous situation where you have to draw it. You may never have to fire it, but you should have the mental mindset to be ready to do so and to deal with the related circumstances.
Harry Bonar said,
They will arrest you, confiscate your weapon and you'll be treated like a criminal. Your case will go before a Grand Jury and hopefully the will file a "clean bill" on your berhalf. You will then be released.
I had to laugh at this statement. Apparently there is a huge stigma associated with being arrested and people feel outraged when they get arrested even though they were the good guys in a bad situation. The reason why I have to laugh is that the stigma and outrage associated with 'being treated like a criminal' is just an overblown misguided interpretation of the events. It isn't that you will be treated like a criminal if arrested, but that you will be put through the first part of due process. That process certainly will include things like handcuffs, mug shots, holding cells, and if the charges are filed, the whole court section of due process.
A buddy recounted an incident where one of his friends was arrested at the airport for a handgun. The friend had a CCW and unintentionally left it in a carryon bag that was spotted by the security folks. So the friend was arrested. My buddy was outraged by the arrest because the friend was cuffed in front of other passengers, led away in cuffs, and taken to a holding area where the friend was processed. In other words, the friend was treated like a criminal. In reality, the friend was not treated like a criminal, but treated appropriately as per the process.
So if you are in a shooting and even if it is justified, you may get arrested and the reason you may get arrested is that it is part of the process. Unless things are 100% or better that you operated in true self defense, you may be arrested simply as a part of the investigative process that would be done for any shooter until the time that officers work out what happened exactly. If they can't, then expect to deal with the grand jury and/or a full blown trial.
These are just the costs of doing business with a gun. There are inherent risks associated with the whole process.