Panic by far and away isn't an "indie developer". In the Mac dev space, they're pretty big.
There have been countless posts on HN from smaller devs getting their apps immediately pulled upon an update review for something they got no warning for.
Panic isn't a tiny player, I agree, but they're not Uber. there's a possibility the human reviewer assigned to its case hadn't heard of the company. If I were a reviewer and I had no personal experience with the app or did not immediately recognize the name, I'd be inclined to treat them just like anyone else.
I would not be surprised if the big hitters are not already tagged as such when the reviews get sent in. Whether there's something as small as a tag for the reviewer to know, or even a separate queue, I sure as hell can bet they go through an expedited and streamlined review process for their updates and such. They're the bread and butter of the App Store, so it's in Apple's best interest to treat them well.
There have been countless posts on HN from smaller devs getting their apps immediately pulled upon an update review for something they got no warning for.