I've shot video (but never any still photos) of a very similar scene from the platform of the MAX Washington Park station looking "east" toward downtown Portland. Similar lateral and vertical curvature. Unmanned, isolated, very deep underground location; security cameras yes, hassle factor no. Of course, by the time anybody would have shown up to question us, we were already up top and inside the gates of the zoo anyway. Lingering for more than a few minutes with tripod and big-old photo backpack is sure to draw someone's attention at such places.