What I meant was difficult to manuever because of being in a confined area which increases risk of running aground since you are in shallow water.
It really depends on the geography of the area. I would not hesitate to dive out of a large sailboat in SE Florida near shallow water. If a storm popped up just head East to deep water. The inlets here are well marked and you could easily just head in during a bad storm, even at night. No big deal.
However, other locations may not be that simple. For example, in the Bahamas the squalls can pop up very quickly and they tend to be much more violent than the storms we get off SE Florida. When you are near the reef you need to keep a lookout for large coral heads near the surface that pose a threat to your boat. There are no channel markers in the remote islands marking deep water when cutting in between rocky islands. It is very risky to navigate a large sailboat through an area like this during a storm when you lost visibility and you can't do it after dark. If caught in a storm like this you would just typically head out to deep water and ride the storm out then come back into your anchorage/harbor when the weather clears. Hopefully the storm clears before dark or you may be out, and at the helm, all night
. In places like this it is much less stressful to just keep the large sailboat anchored somewhere safe and dive from the dingy.