Was the security officer in question, did he/she work for Amazon? Or was he/she a contractor to Amazon? Most security officers are contract
Contractors (security officers) can be hung out to dry (terminated) and Amazon can say the security office was not following the Standard Operating Procedures of the contract.
This is how corruption in corporations works. It's all about not putting things down in writing and setting unlawful expectations all while adding layers of obfuscation to avoid personal liability.
Amazon will fire the guard, the guy that hired the guard, the manager of the floor, etc. All the way up to middle management. And they'll do that HAPPILY because the cost of firing that group of people is a lot less than the cost of having a union in their warehouse.
It's quite unlikely that the guard was a direct Amazon employee.