A few points:
1. Unlike easier beaches that have a long, gentle slope where the energy of the waves can dissipate over a greater distance, Monastery's beach is very steep. You can be in water too deep to stand in as little as 5ft off shore. The energy of the waves has very little room to dissipate, so it breaks with heavy force in a very short distance. This can easily knock you over, drag you around, rip off gear that's not positively attached to you (ex. fins, mask, snorkel, regulator), and pull you back underwater.
2. The waves break hard and recede, only to break hard again. If you get caught up in this surf you can be caught underwater very close to shore in water too deep to stand and tumbled end over end. Always have your regulator and mask on your face and hold them in place when entering/exiting. When you tumble you can and will lose sense of up and down and will have no idea which way is to the surface. Always have your regulator in your mouth. A snorkel is not enough. I've had the dry valves on the top of dry snorkels get stuck in the *closed* position when they get tumbled. When this happens you can't breathe in air even if the snorkel is above the surface because the flap at the top is stuck closed.
3. The sand is very course and the grains are big. If you're standing on the beach and the water rushes up past you, the receding water will actually wash the sand right from under your feet, compromising your balance to a large degree. It will do the same when you're trying to crawl or walk out.
In general, do whatever you can to get out of the surf zone as quickly as possible. When you're in the water, just swim swim swim and don't worry about anything until you're out of the surf zone. If you drop something, forget something, whatever, just GO. Swim away from the surf.
If you're exiting the water, as soon as you touch shore it's the same procedure. Go go go to dry sand and don't stop until you do.
Waves come in sets. A set of big waves for a certain amount of minutes and a set of smaller waves for a certain amount of minutes. Sit there and watch the beach for 15-30 minutes to get a good idea of the wave sizes, and time entry during the smaller waves. Same with the exits. Try to time it so you ride the crest of a wave (during the period of smaller waves) that plops you as far inshore as possible, and go go go.
If you get caught in the surf and can't make it to shore, consider swimming back out where the water's calmer outside of the surf zone and recollect yourself for another attempt.
Enter and exit on the far north or south ends. Never the middle.
If the waves rise above your kneecap, consider not going in.
The area around the pinnacle that you can see offshore is around where the underwater canyon is located. It drops almost vertically to thousands of feet deep.