I've decided that I'm going to drive to the walgreens 4 blocks away to go #2
Would you rather just go off on the side of the road to do this?
It's not like people will see you in the store. And I'll make sure to put paper over the seat.
The restrooms are there for people to use them, so as long as the manager is ok with it you are free to use whatever bathroom is available. It makes sense that you would rather not go poop on the side of the road, but instead use an actual bathroom.
My #2 is runny I need to go now.
Oh, I hope you can make it to the store in time! The employees will definitely understand your situation as restrooms are restrooms, and it's great you are in a pharmacy as well in case it's more than that!