This might sound like a really corny topic, but I just watched Saw III. In the story there is a lot about revenge, and the case kind of reminded me about Niko's lust for revenge.
What if Niko and Dimitri, and anyone else Niko wanted revenge upon (Darko maybe?) were captured by Jigsaw, and put to the test? What do you think Niko would do and how would he react to the tests?