I wouldn't necessarily say Pac got crazier/wilder during DR days - moreso more ruthless and I think it has more to do with getting shot at, betrayed, and getting locked up then DR putting battery in his back. From the convo he had with Monster Kody he doesnt sound amped or gassed to be with DR or Mob Piru and was well aware of the transactional aspect of it (Pac gives sales/notoriety and receiving goons/protection). Pac wanted get revenge on his enemies and studied Machiaveli - he was bound to get more ruthless and coldhearted anyway, it just coincided with DR and got amplified but the whole DR drama is more of an outcome/symptom not the root cause. BTW, I think there was a part of 2pac that resisted this more ruthless side that's been developing and that conflict gave us some of the best introspective tracks from him - Krazy, Staring thru my rearview, etc.