Not sure if this was posted as self parody Chadwick, but you should have been in the "outer" lane, post-turn. I've watched this over and over now about 10 times, and I'm almost 100% certain you went into their lane, rather than maintaining yours, and expected the Red Cross vehicle to enter the Must-Turn-Left lane.
Why didn't you just follow the grey Nissan in front of you? They navigated that turn properly.