You can't fire someone over the phone anymore!
The scene where his colleague tells him the company has fired him on the spot just couldn't happen.
They could only start dismissal proceedings after a full investigation and then it would also have to be in writing. Locke would then have the chance to appeal the decision.
Firing him over the phone would result in an unfair dismissal charge on the company and Locke could sue the pants off of them.
"Perhaps he's wondering why someone would SHOOT a man before throwing him out of a plane"