You've seen them on duty, many times, sometimes close-up. You know what they look for. So you don't leave anything for them to find. You go through it all in your head, very precisely and very exactly and very carefully. Just as carefully as you would mark the play card you knew for sure was going to win you a fortune.
People say that knowledge is power.
The more knowledge, the more power. Which makes you just about the most powerful person on earth. When it comes to killing people. And then getting away with it. Life is full of decisions and judgments and guesses, and it gets to the point where you're so accustomed to making them you keep right on making them even when you don't strictly need to.