The speaker, not seeing any signs of regret from person X who did not take the chance to counter attack, believes that person X made this choice deliberately, and that person X still believes in the correctness of his actions even after the fact.
The question means: what is your mindset, person X? Why do you believe, presently, that you made the right choice? What are you doing?
If it's obvious that the person has realized their actions have failed, then you might ask どういうつもりだった -- What was your mindset at the time, which you no longer hold? What were you intending to achieve, that you have not achieved? What were you hoping for?