What's Batman's worst mistake in BR?

[Catbat]

Thank to you all for your opinions!

Personally, I think Batman should have tried to retrieve his batrang from the Poodle Lady but frankly it's not that he forgot to do that – other members of the Circus Gang began to attack him and they kept him busy, thus allowing the Lady to flee... Unfortunately, it's also true that that specific piece of equipment later helped the Penguin frame Batman...

Secondly, Batman greatly underestimated the threat posed by Catwoman and she made him pay dear for that – on a physical level, she proved to be a very dangerous foe for him. Generally speaking, she had a talent for confusing Batman before assaulting him (i.e. the "how could you I'm a woman" ruse  or, even more surprising, the way she could stimulate him through the batsuit with her clawed hand).

[Catwoman]

How could either Batman or Catwoman be thinking about sex after what had just happened, including the Ice Princess dying thanks to their joint incompetence? 

they knew how to prioritize.

Batman should have prioritised saving the princess and when that failed, apprehending Catwoman and taking her to the police to absolve him of wrongdoing and implicate herself and the Penguin.

I'm not sure how they could think about kinky stuff after what had just happened.  They must have thought the girl deserved what happened to her to be so blasé about it all.

must have.