Couldn’t she just have run down the raising bridge to the level part? It looks like it.
There is a gap at the bottom when the bridge is raised. She slid right in to it. This site has pictures and drawings. Much better coverage.
No, she was elderly, and as it raised, the end 10 feet away dropped as it pivots downward. It’s not like a hinge. So when it moved, there was almost immediately a gap wider than she could manage, and it opened to the concrete base 50 feet below. She fell and landed there.
Kind of imagine the pivot point being a distance in from the gap. As the center raises, her end dropped below the roadway.