Ok, time for some assurance. I'll give you a quick run down of a different species. I have a A. seemani that's about four inches, and she will baracade herself in like that, and even dig a burrow. She waits until she molts, and eventually digs her self out. Usually, she leaves no entrance, just closes it up and she's sealed off. She usually stays down there for three to four months at a time. No kidding! She's a bit higher strung than your typical rose hair too, so no worries, your spider won't die down there. In fact, this may be exactly what she needs. Either she is just mellowing out, or she is getting ready to molt.
On that note, just curious how you're cleaning out the tank. If you're emptying all of the dirt and cleaning it out every three weeks, that might be why she went under the log. She may be a tad bit stressed. They need a couple of weeks to explore and make themselves at home. Once they've done that, life is good. It may be possible you've been changing things on her too quickly. It really seems like cleaning her home that often would be good for her, but really, they don't need anything like that very often at all. I have a couple of Rose Hairs right now that have homes that haven't been fully cleaned in about a year and a half. You have to remove the remains of the crickets and do a little bit of small scale cleaning, but the dirt, especially if its dry like Rosies like it, doesn't need to be changed very often at all. You're probably talking about small scale cleaning, but if not, something to think about