What is the main reason for having a person positioned immediately outside a confined space whilst work is taking place inside it?

The main reason for having a person positioned immediately outside a confined space during work is to ensure safety and facilitate quick response in case of an emergency. This individual serves as a lookout and can monitor the situation, communicate with those inside, and initiate rescue procedures if necessary. Their presence helps protect the workers from potential hazards associated with confined spaces, such as toxic atmospheres or unexpected equipment failures.