Two days ago I spent about an hour observing and photographing the semi-terrestrial snail Melarhaphe neritoides* in a rock pool by the Aegean Sea. This was in the morning and all of the snails, save one, were dormant on the rocks above the water. The one odd Melarhaphe was in the pool crawling slowly on the rocks.
The sea was rough and every time a wave breached over the raised edge of the pool, the water level in the rock pool went up and submerged the snails on the rocks for a few seconds. But the snails appeared oblivious to the water and remained inside their shells. Perhaps, they were waiting for the night time to start their activities. It may not be a bad idea to visit the spot after sunset to check up on the snails.