Yeah, I've seen this happen with a good friend of mine I went to high school with. Super good guy, nerdy, smart, always wanted to be a police officer- hated the corruption, wanted to make a difference right? In the 10 years he's been on the force he's gone from beat cop to detective to State FBI Special Agent, and his thinking (illustrated on Facebook) has gone from blasting NWA's "F&$K The Police" to posting pictures of himself all suited up in his FBI gear complete with skull and crossbones patch running around in the woods "Looking for perps". He's got gold skull and crossbones grips on his service weapon. In his mind it's all "Ninjas and Pirates" but that, coupled with his descent into the thinking that "If you weren't guilty, you wouldn't run, and if you aren't guilty, you have nothing to fear from the police" is scary.
“You can’t change the system from within, it will only corrupt you.”
When you look into the abyss the abyss looks into you. Right?
You have to have the self belief and fundamental aim to make things better or leave it to beaver.