No, I'm not going to be doing any cooking at the hotel. I would've stayed in Airbnb rental if I was going to cook. The way these seafood markets work is that you select the seafood you want and the vendor prepares it all for you right there on the spot. Say there's live fish you want swimming in the tank. You tell them you want to buy that fish and how you want prepared. If you want it raw and sashimi style, they will kill the fish right in front of you, filet it, and slice it for you. You can eat it on the spot or you can take the raw fish slices upstairs where the entire floor is restaurants you can go in and sit and eat your fish. You pay the restaurant around $4 per person. What that $4 buys you is table for you to sit and eat. They provide you with free side dishes and vegetables to eat with your fish and free condiments and sauces. And they will take the leftover fish head, bones, and tail from the fish you purchased and make you spicy fish soup to finish out your meal. It's really great system. So it's like going to the restaurant and ordering the food except you pick out the exact seafood you want and how you want it prepared.
Here's video how it works. That guy in the video doesn't eat raw fish so he had the fish grilled and also got some shellfish steamed. He didn't get the spicy fish soup at the end of the meal because he had his fish grilled whole instead of eating it raw. He did get some ramen though.
There are several large seafood markets in Busan. The above video is the one I'm staying next to. There's also one market that specializes in crab which I'll probably visit as well.
http://boundforbusan.com/2015/07/gijang-crab-marke.html