Final answer:
The author's use of a false dilemma in the job manual makes the employee doubt the manual's credibility by presenting only one option and excluding other valid alternatives.
Step-by-step explanation:
The author's use of a false dilemma in the given job manual excerpt impacts the overall argument by making the employee doubt the manual's credibility because other valid options are missing from the argument.
The false dilemma presented is that the employee must always put the customer first, even if it goes against other company policies. This creates a binary choice for the employee and makes them believe that there are no other options or ways to handle situations.
In reality, there can be a balance between pleasing customers and following company policies. The employee can take customer concerns into consideration while still adhering to the guidelines set by the company.