It does look as if the dog was being dangled in the water. "There is actually a platform under the water [which] the dog is standing on," says Quaid, who wasn't on the set at the time (this particular dog not being his character's pet). The dog was reluctant because that wasn't the side it had practised going..."
https://www.theguardian.com/film/2017/may/04/dennis-quaid-a-dogs-purpose-animals-abused-on-set
Jesus Saves
