This is partly a continuation of this question, since that one was already closed, but my question is about a specific problem encountered the last time I cooked scallops.

I got the pan up to a reasonable temperature and put the scallops in, and as they were cooking, TONS of water came out of the scallops and filled the pan. I poured it out, continued cooking, and more water came out. Several iterations later, I thought they were done, but they were still very raw inside, so we ended up tossing the batch (it definitely wasn't sushi grade).

Where did all the liquid come from, and is there any way to avoid that the next time?

This is partly a continuation of this question, since that one was already closed, but my question is about a specific problem encountered the last time I cooked scallops.

I got the pan up to a reasonable temperature and put the scallops in, and as they were cooking, TONS of water came out of the scallops and filled the pan. I poured it out, continued cooking, and more water came out. Several iterations later, I thought they were done, but they were still very raw inside, so we ended up tossing the batch (it definitely wasn't sushi grade).

Where did all the liquid come from, and is there any way to avoid that the next time?