A few examples (in approximately increasing order of controversy):
If you proceed anyway...
- Identify knowledge that may be dangerous. Forewarned is forearmed.
- Try to cut dangerous knowledge out of your decision network. Don’t let it influence other beliefs or your actions without your conscious awareness. You can’t succeed completely at this, but it might help.
- Deliberately lower dangerous priors, by acknowledging the possibility that your brain is contaminating your reasoning and then overcompensating, because you know that you’re still too overconfident.
- Spend a disproportionate amount of time seeking contradictory evidence. If believing something could have a great cost to your values, make a commensurately great effort to be right.
- Just don’t do it. It’s not worth it. And if I found out, I’d have to figure out where you live, track you down, and kill you.
I don't understand your second sentence.
I believe that what he's saying is that with power, people show their true colors. Consciously or not, nice people may have been nice because it benefitted them to. The fact that there were too many penalties for not being nice when they didn't have as much power was a "corruption" of their behavior, in a sense. With the power they gained, the penalties didn't matter enough compared to the benefits.