Kane & Lynch 2: Dog Days

ok the guide above was a little vague so i'll try and point some key issues out...
1 it doesnt matter when you try for this i.e. if your scum/reliable/shifty etc. killing yellow carded players wont harm your reliability, i dont think killing traitors improve your reliability, becoming yellow carded will damage your reliability score and finaly it doesnt matter if you escape or not or die and spawn as a cop. so watch your fire and only target the bad guys... well good guys i suppose. dont friendly fire at all and kill the cops and the more cops you kill the quicker you will get this, round time depends on you but from fresh it took me around 5-6 fragile alliance games, under cover cop and cops and robbers will also work n rank accordingly tho

All you have to do for this achievement is not become a traitor or shoot any friendlies so you don't get a yellow card. If you want to do this achievement a quick way just gather up some friends (minimum of three friends to make four players to start the heist) and pick the map called "Financial" and just dont kill any of the guys and run down into the loading bay with all your friends and get killed this is a very fast way to get the achievement because you dont have to complete the round to get your criminal loyalty up. Before you know it, you will be a saint.

I got this for me and a friend by not killing any players or AI enemies, while not grabbing any money whatsoever when escaping.

To be more specific we played Cops & Robbers on Dry Dock, all four rounds. We both spent rounds 2 & 4 killing the other team to grind kills as the cops. Not sure if this is a glitch or not but it worked back to back. We escaped together both times, while sometimes leaving the third player behind.