I had one experience in a strong downcurrent in Cozumel years ago.
I've been diving Cozumel for about 35 years, with some long gaps between, about maybe 8 to 10 visits. First time diving there was I think, around 1988 and I went with Aqua Safari (they were good enough, I knew no better), did Dive With Martin on the next trip (I was not impressed). Next trip (years later, maybe early 2000s) I was with my wife and we decided to try a "boutique" dive op, and we went with Living Underwater based on recs from this board.
We loved diving with Jeremy. After meeting us at our hotel the night before our first dive, we chatted, handed over our gear, talked about our experience. At that point I had been diving for 10 years (not frequently, but I grew up with a snorkel in my mouth and am very comfortable in the water) and had more than a little experience. My wife had some post certification dives in Hawaii and Thailand, but was still pretty inexperienced. Jeremy told us we would need to do a checkout dive first the next day. I was fine with that, my wife got a little huffy, but eventually said OK (that's how she rolls sometime, and other resort dive ops she had been with never needed anything other than a glance at her C card and her signature on the liability waiver form).
So next day we did a checkout dive in a sandy shallow spot, demonstrating boyancy, remove-the-mask drills, regulator recovery, etc., really basic OW cert stuff. My wife did perfectly well, although extra-fine boyancy control was something she still needed to work on (even I could see this, certainly Jeremy did). I chuckled and went along (Hey, I was underwater in Cozumel, so happy enough). In fact, my wife did need to brush up on those basic skills. Jeremy was patient, supportive, helpful, and gave her the attention and time she needed to relax, get comfortable in the water again, and demonstrate/refresh her skills. He was absolutely right to require us (well, maybe her, but it was always referred to "us" together) to go through all that before we went diving the next day. We did, and my wife did just fine. We were having a blast.
A few days later in the week, we had an interesting experience on one dive.
I don't recall the location. There was some decent current, as is typical in Cozumel, but nothing that seemed extreme. We were diving along some wall, I think we had just 4 divers in the water, plus 2 DMs. One of them was Jeremy, he was with me and my wife - not hovering right on top of us, but nearby, pointing out critters.
We were cruising along a wall, probably around 70-80 feet, comfortable, enjoying the dive. All of a sudden, I noticed sharp pain in my ears, which immediately seemed wrong, since we had been moving along the wall laterally and my ears had cleared fine when we started the dive. Ouch, more ear pain, I cleared my ears again, then spun around to look for my wife, and did not see her - I was surprised to see I was densely surrounded by tiny bubbles, going up, or maybe down, I couldn't tell, maybe the bubbles and I were moving together. I felt quite disoriented, took a look at my depth gauge - I had just passed through 100 feet, and was sinking. And things were getting darker (literally, and now I realize, figuratively, too). Colder, too. Things were happening fast and I was getting way too deep. I started finning hard to try and stop sinking. With my right hand I reached for and was fumbling with my inflator hose, my left hand was fumbling with the weight-pocket release pull on my BCD.
Before I managed to either press the inflator button or dump weights, I felt a very sharp tug on my leg. WTF?! My guage was showing 120 feet and dropping. I looked down, and saw Jeremy below me, reaching up with his hand around my ankle - he then pulled himself up (or pulled me down) and grabbed my BCD sternum strap across my chest - tightly (this wasn't a gentle tug, this was "the deathgrip of authority"). Very confused, I looked at him and then saw his other hand was firmly gripping my wife's tank strap, as she was below him (she was still attached to her tank). So he had me in one hand above him, and her in his other hand, below. He had apparently grabbed her and hauled her up to where I was (around 120 feet), she was dangling below him. He looked very busy.
His hands full, he locked eyes on me, gave me a hard look, nodded his head upward - and away from the wall, out towards the open water. I also saw his eyes flash to my hand on the weight pocket dump string and then to my other hand over the inflator hose button. He shook his head gently side-to-side, and looked at me again. I nodded back firmly to acknowledge. All this transpired in just a couple seconds, but the messages seemed pretty clear. I took my hand off my weight dump string, kept the other one off (but near) the inflator button. We all finned up and outward, away from the wall. In a few seconds, it seemed we popped out of it, in relatively calm water, slowly finning upward and away from the wall. Depth gauge showed about 110 feet. Jeremy let go of me first, turned to my wife, she signaled OK, then let go of her (but kept his eyes on her and stayed close, I noticed). We all slowly and calmly finned up to 90, 80, 70 feet. We stopped there and settled down for a moment, checked air, boyancy (and heart rate...), all good, everyone OK.
We could see the other pair of divers with the other DM in the distance, they were still happily cruising along the wall, had not been sucked down, and had not even noticed us. Jeremy, me, and my wife began a gradual ascent while drifting laterally along the wall, we went up to 30-ish feet and continued the dive just for a short while, before heading up for a long safety stop.
We get back on the boat, Jeremy is all business, all matter-of-fact, quietly handing out dry towels and water bottles, helping us stow our gear. Me: "Well, THAT was certainly interesting, wasn't it?" My wife: "That was crazy! What happened?" Jeremy just smiled, paused, and quietly said, "Yes, it was interesting. Mother nature was testing us today. We passed." Then he handed us some snacks, and went back to tidying the boat.
I'll dive with that guy forever.