Yeah, I was grasping at straws. It's hard to explain things that seem to come naturally.
Every set of 'rules' I've found online suck for one reason or another.
So, one British site had a rule regarding "V-ing (simultaneous)." I guess that means that rule only applies if the actions in both sentence and clause go on at the same time. If not, I don't know what it means.
But, some of their rules make for strange sentences here. It's always something.