Is there a way to determine whether it's an engine, or just the ventilation system?
/serious question…not shilling
Seems plausible, particularly when we take into account the similar analysis of the video, which shows cyclical variations that might be caused by waves (on water). I just don't want to be too eager to buy into a theory just because I want to believe it. Good work, let's keep digging.
OTOH, by the end of today, we'll know whether shit's going down that makes this kind of POTUS protection advisable in the first place…