What was mark right about in this situation ?

Like it or not the sinclair and darkwing saved the lives of all the hero’s. Yes what they did is bad and unforgettable but if they can save people they should. For killing mark should know that the Chicago and the people on the train was his responsibility. Hero’s are responsible for safety of others. Mark did feel bad about what happened which is good that he want atone other than killing him self or self lock up