This achievement will pop along with :
When you escape with all three team members being friends (smiley face icon). I had 100 reputation on all three though, so maybe do that to be safe.
THis is easy as you get no favours to beat them up. As long as you don't hit them the reputation will only decay to yellow at most.
When your ready to escape (fitting the fuse) gift them items (shanks work well), or even better give them their own signature items.
See the following for details ;