Anchor: The scuba diver is underwater.
Entailed: The diver is surrounded by water.
Contradiction: The diver is buying a bottle of water at the beach concession stand.
Contradiction: The scuba diver is on the boat taking off his gear.
Contradiction: A person on dry land.
Contradiction: The diver has just surfaced with a giant lobster.
Contradiction: The scuba diver is tanning out on the sand.