Here's all the adjustment I think needs doing to my explanation:
OK - completed a draft round of analysis here.
I think I get your theory:
1. Pole is slanted, so when exhaust pushes the flag off screen, and when the exhaust subsides (e.g. they close the valve for equipment/safety checks) -- the flag comes back on screen, because of this tilt.
2. The flag will be on screen when "at rest", and off screen as it is pushed by the Exhaust.
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When I twist everything in favor of the Apollogist, I still cannot resolve a number of critical issues with your theory:
1. Depressurization procedures only allow for high pressure evacuation for about 1 minute. Yet your theory has this exhaust breeze holding the flag away for about 116 seconds total, after it's first appearance to it's final appearance. This doesn't include the concept of "what about BEFORE the flag first shows up???"
2. What brought the flag onto the screen to start with? (continuation from #1)
3. Why was the top of the flag always SLANTED off screen to the top pole? This is a sure sign of "breeze pushing it on screen", and not being "at rest" per your theory.
4. Your theory has a "grand finale" where the PSI is about 0.1 PSI - that flows the flag to do a 180, and then stay there.