I always wonder in these sort of situations are there people out there who view it like "Well these are obviously bad guys, cooperating and testifying will get a lot of them off of the street and be a colossal blow to this continuing criminal enterprise". Being fair, they have a valid point.
We tend to look at it from the betrayal standpoint only. The rat doesnt deserve any credit for giving up others because they only do it to save themselves...but what if their testimony gets 10-20+ violent criminals off the street? . Isn't that a good thing.
That's the boys job not his.