For Nine Tails Lockdown, players can choose to help the Nine Tails or help Crusader Security. Is that a choice that you get locked into, or will you be able to change your mind, play both sides, flip back and forth at will? How does that choice actually manifest?

So the choice actually manifests itself based off of if you have a CrimeStat or not. If you have a CrimeStat, then you'll get the Nine Tails missions. If you don't, then you'll get the Crusader missions. If you get a CrimeStat while you're in the Crusader missions, then you'll get kicked out and you'll be given the option for the Nine Tails missions. And then obviously if you have a CrimeStat and you get rid of it during that time, then you should be able to have the Crusader missions.

So there's not a checkbox or some weird piece of non-diegetic UI.

It really is all based off your CrimeStat. So you clear it, you should get Crusader; you have it, you should get Nine Tails.