Question

why must proper technique be followed for a patient transfer?
to maintain comfort
to avoid the patient becoming annoyed
to prevent injury
to avoid a lawsuit

Explanation:

Proper patient - transfer techniques are primarily about safety. Maintaining comfort is a secondary aspect. Avoiding annoyance is not the main reason. While avoiding a lawsuit might be a consequence of proper practice, the direct goal is to prevent physical harm to the patient during transfer.

Answer:

To prevent injury