What first aid method is crucial for someone experiencing pesticide exposure?

Moving someone away from the source is a crucial first aid method for pesticide exposure because it helps to remove the individual from the harmful effects of the pesticide. This minimizes further absorption of the chemical into their system, reducing the risk of serious health complications. By relocating the person to a safer environment, it allows for better assessment of their condition and appropriate medical care to be administered without ongoing exposure to the toxic substance.

While other options may seem helpful in certain scenarios, they do not directly address the immediate need to prevent further exposure to the pesticide. For instance, immediate ingestion of water may not be advisable depending on the type of pesticide, as it could lead to further complications. Cooling body temperature is not directly relevant unless they are experiencing heat-related issues, and applying antiseptic could be inappropriate if there's a significant chemical burn or reaction from the pesticide. Hence, prioritizing the removal from the source is the most effective and appropriate first response in instances of pesticide exposure.