Got it on first try. I spotted immediately, due to the way the locks need to be opened, that only one can work. Once knowing the correct target, route was sort of forced (no free room).
Having seen Alazeh's comment I assumed I'd never get this level, however it only took 3 or 4 goes, which is a miracle for me. I settled on an exit early and knew I'd have to approach it in a particular way so took care on the route.
Insights