My opinion is that "desperados" like Dillinger had a lot of courage and were very unpredictable by being very trigger happy. But as it was already said in one gangster movie something like "huge balls, but no brains". Many of the "desperados" who were closely tied to some members of the Outfit, by the mid 1930's were killed by the Mafia mainly because of the sensitive jobs they previously did for them like the professional hits in the massacre or on Aiello and Barker, which were executed with machineguns (some from a very long distance with military precision). Also, when Fred Burke went to prison while his buddies from the massacre were hunted down all around the country by the Mafia, Burke was personally visited in jail by Capone capo and connection guy Phil D'Andrea and both of them had a short private talk. Some of the prison guards and the warden at the time, speculated that the short chat was for Burke to keep his mouth shut or else.