nah, I can handle it. I just got to make sure to do some back ups before handlol, I hear ya, phpMyAdmin controls EVERYTHING in the site, and one slip up can cause catastophe. But, as long as you don't delete anything you're good. I can walk you through the steps to show you how easy it is when the time comes.
Tables are split between topics & posts yes, but the posts ( messages) table will have every single post in there, whether it's a topic starter or reply to a topic. The main reason their split into 2 different tables is so the database can use the topics table to mark topics as sticky, locked, etc. Trust me, I know what I'm talking about. If you have any kind of voice chat IM on your PC pm me and I can walk you through itafraid the phpmyadmin won't be of any help.
If I'm reading it right the count is split between topics and posts. So I really can't use it to find out who made the 100k post.