THERE MUST ALWAYS BE A BATMAN: When Batman would be KO'd, you may instead KO another friendly character with a point value of 25 or more and turn Batman to click #1.
If you played 6 of these Batmen and one would be KO'd, then choosing another Batman to be KO'd, then he would be, then choosing another batman....

Is this an infinite loop?

Not infinite, no, as that would result in stalling, at least in an actual tournament. You'd have to choose 1 to actually KO. However, you could essentially chain the triggers to heal up all the remaining ones each time one would die.

In theory, yes.


However, from the tournament rules:

Tournament Integrity: WizKids reserves the right to issue rulings during a tournament to preserve the integrity of that tournament. At the discretion of WizKids, actions may be taken to correct rules "loopholes" or exploits deemed disruptive to the tournament and the general spirit of the game. In extreme examples, this may include disallowing force builds and/or disqualification of a player. As a reminder, Wizkids also reserves the right to disqualify players that do not follow rulings or directions given to them by a tournament official.

I guarantee you that if someone tried this at an official WK event as an attempt to run down the clock, this would most definitely not be allowed.