The Field Engineer is not rated as a diving chronograph. It’s engineered for high water and dust resistance and each chronograph is pressure tested, but I use a floating crown to ensure high shock resistance rather than the screw down crown necessary for diving rating. Swimming pool, Yes. Diving No. (Incidentally hot showers are a bit of a No as well as hot water expands metals and soapy water has low surface tension and can penetrate seals.
That said, a little bit of shallow water commercial diving is a good opportunity to verify my own Field Engineer is still waterproof to a reasonable depth, and Shaun kindly obliged.