Yes. Have, but only with a least one other diver and with a safety person on the boat. You have to be careful to decompress property. Definitely not for an inexperienced diver.
Have swam in the ocean, over the Marianas Trench, some 36,000 feet deep. Freezing cold, in and out. Then lounging on the deck in the warm sunshine. Definitely wakes you up from the shock.