Just a thought, as I exited the front bog recently at cruise altitude.
My feet and ankles are used to a floor at 2.5-3.0 degrees nose up for the short walk, or the loiter in front galley to liaise with CC.
Even when I'm inspecting the plumbing I'm aware of the step climb the F/O has negotiated in my absence
Can anyone explain why Monsieur Le Capitain did not notice an unusual deck angle during his sprint to the flight deck? Any of us who've walked in the aircraft during initial climb, especially on empty positioning sectors as pax, have been aware of the deck angle and the extra effort to walk uphill.
This must have been a tactile clue to the standing crewmember on his return to the "control center" and yet it failed to trigger a suitable response from him? As a non 'bus driver I felt like getting the thread away from all the exotic Laws various which others have said tend to make diagnosis more difficult.
No AoA probes, no vacuum/wind powered AHs, no reference to expensive ADIRU sourced blue-side up, brown-side down displays, just the plumb bob on a string which we all are when airborne. Yes the craft was probably speeding up, slowing down and bucking around, but the general trend could have been obvious to a standing & walking crewmember, uncontaminated by the confusion forwards of the cockpit door
After that Eurocents worth, back to the darkened room.
