Final answer:
The Security Guard should call for help and stay with the injured individual until medical assistance arrives, respecting their wish not to receive first aid while ensuring their safety.
Step-by-step explanation:
When a Security Guard encounters an individual refusing help after an injury, the guard should respect the individual's wishes but still act responsibly. Although the Security Guard is trained in first aid, they should not demand that the individual accept help. However, it is important to ensure the person's safety, so the guard should call for help and remain with the individual until ambulance or medical assistance arrives, in case the situation worsens or the injured person changes their mind about receiving aid. This action demonstrates both concern for the individual's autonomy and responsibility for their well-being.