Yaaaay! Thor was running around my office after hours, and he took the initiative to go on his potty pad.
This was a big part of why I decided to train him on pads: I noticed that when he was playing, he would pee anywhere he happened to be when the urge struck him. I assume he didn't want to stop his fun.
We are both back from our respective trips, so it's time to continue the count. I think he's over a week now. I'll need to go back and check.