The bear enclosure has survived relatively unchanged since the zoo first opened in the 1930s. It is/was virtually bomb-proof, so for something like this to happen underlines how freakishly tragic this incident is. There’s some big trees in that area of the zoo so anything could’ve happened- they could’ve got out and onto the main road for example.
The timing couldn’t have been more tragic either considering the zoo was celebrating 90 years this week. Personally, it brings back some haunting memories of the chimp escape 10+ years ago.