Agree dog owner routines are predictable, including locations likely to be, and I say this because I own a dog. In terms of the "window of opportunity", apparently she was spotted at 9.10 and phone found on the bench at 9.35. A lot can happen in 25 minutes. Just think of how people over the years have been abducted off the streets in a flash. They say she was logged on a Teams call, video off and on mute. If she had headphones on, she probably wouldn't have been aware of someone behind her. I can't imagine she'd have fallen into the river and not cried out for help. Also, can't believe she she'd travelled so far and fast, such that she was out of sight when her phone was found. These are just my thoughts....