> You bribe one employee to pretend someone called and authorised a huge transfer. OK. But then a different random employee has to confirm it. How do you bribe them?

So first bank employee I bribe is one who can update the phone number on your account to one I control (or even better, an employee from your telco who'll let me port your number to my burner phone), the next employee I bribe is the one who pretends the call came in. The different random employee then just does their job confirming the transaction with a call to me. Bingo - I have your house payment...