Re: 'how its possible to take a $1 million out of a ATM in a day?'
"I always wondered what's to stop all the mules just running off with money?"
Strong attachment to their family members, friends, limbs, life etc. Dislike of concrete shoes.
If you're a professional crook, then both your reputation and patronage are much more important than a single "score". Even if you go on the lam, you'll be running for the rest of your life. Setting yourself up as an example to be made "pour encourage les autres" is bad wherever you are, but when working for OC it would seem pretty fatal. Probably painfully so.
I'd also expect them to be working in a pair or small group, with some amount of collective responsibility.