What is the key action to take after a diver has an oxygen convulsion but is stable?

After a diver experiences an oxygen convulsion but is stable, the key action—surface decompress—addresses the essential need to remove the diver from the high-pressure environment that could exacerbate the risk of further complications associated with oxygen toxicity. Oxygen convulsions typically occur due to the effects of high partial pressures of oxygen, which can lead to various physiological responses. Thus, by surfacing or beginning a controlled ascent, the diver can be transitioned back to a normal pressure environment, significantly reducing the risk of another convulsion and allowing for more controlled management of the diver’s condition.

In addition to enhancing the diver's safety, surface decompression can facilitate the provision of necessary medical attention once the diver is dealt with at the surface level. This step is crucial because while the diver may seem stable, residual effects from the convulsion could pose further risks if not carefully managed.

Monitoring at depth, administrating oxygen, or ascending to the surface without a structured decompression plan might not rectify the underlying problem effectively and could expose the diver to additional dangers related to pressure changes or oxygen toxicity. Therefore, the structured approach of surfacing safely is fundamental to the management of the situation.