Well, let's be fair. Batman was drugged and not at the peak of his ability. The criminal in question had stuffed the pistol down the front of his trousers. Now, either Batman lets the criminal take the pistol out before taking him down, or stops him before he can pull it out. In the former, I guess that Batman at the peak of his abilities would still prefer to disable the shooter before the weapon comes out. The only time he allows a gun to be pointed at him tends to be those moments where he scares the beejeezus out of them and makes them drop the gun - which would be completely undoable since the mook had just carried an unconscious, drugged out Batman through the sewers - I Think at that point the fear factor had gone away.
I just want to point out something else. You cannot kick a gun and expect to pull the trigger. Not even Batman can use his little toe to wiggle through the inches of combat-boot to pull the trigger. Batman kicked the gunman's gun-hand and at that exact moment the mook pulled the trigger. The mook was just a bit too trigger-happy...not anymore.
Just to clarify again: Batman did not make the criminal shoot himself. He just stopped the gun from being pulled out. It was entirely the criminal's fault to jump the gun.