This was my very first thought, he didn’t appear sedated, but you just never know. He loaded into their trailer instantly, was well mannered at the park they hauled him to the first time, and I rode him in an smaller open field with a gravel track around it with park benches, picnic tables, and a covered area. There were definitely plenty of things to look at and people walking through the trails around the field area, so definitely a lot of opportunities for him to spook or bolt that day, but he was a complete gentleman.
The setup at the ring I rode with on disaster Saturday was a very “standard” barn setup and nothing out of the ordinary at the indoor that I would consider unusual or something that would be spooky for the average horse.