But as Antonio Madrazo, sales manager of Scuba Du, told me, “You can drink anywhere. People come here to dive.” It’s true. From our patio at the Presidente InterContinental Cozumel Resort & Spa, I could see two tiki huts: one stocked with tequila and abandoned at dusk, the other stocked with dive gear — and always packed. “Just wait until you see the Palancar Wall,” Antonio said. “Your jaw will drop.” With a regulator in my mouth? All their well-meaning advice still sounds ridiculous, but as I fight to stay horizontal, maintain my depth, slow my breathing, I resolve that if these people can do it, so can I.