Agreed - it's not out of the bounds for the characters to move a bit between shots for dramatic effect, but it requires us to believe that the characters have dramatic motivations...
Sometimes the set pieces have those, too. The big generator things no doubt are on antigrav pedestals - but perhaps some of the wall elements swing on hinges, too, so that the control panels on them can always be viewed simultaneously with the piece of machinery they are keyed to control?
It's symmetry suggests to me that it may have to do with the engines (there being two of these... and they're symmetrical). Perhaps this is a monitor of the engines and reactors, but also includes information which is related to the ship's navigation capability?
We could always say that in navigational situations where the helm doesn't respond properly, steering by asymmetric thrust is a factor to be considered, just like in today's naval propulsion. Chekov's seeming interest in engines could thus directly tie to the navigation task at hand, i.e. getting the damned ship to as much as agree to turn around.
I still don't think any of the episodes establish any sort of an upper limit or plausible number for the crystals the ship needs for X, be it X=warp propulsion, X=full power, or X=maintaining orbit. Crystals are consumables, and rare enough that makeshift replacements, bypassing and underway maintenance are part of the routine. "Mudd's Women" doesn't indicate gradual loss of power from gradual loss of crystals, thus being in line with "Elaan of Troyius" in that a single crystal gives full combat and warp power. "Alternative Factor" explicitly disagrees, but that's with the paddle things. And TNG is based on the use of a single crystal focus through and through. We can draw all sorts of conclusions, but "X crystals are required for achieving Y" would seem excessively assertive for all values of X.