To come to any conclusions as to what forces are in play which might help explain Chris's observations, the problem lies not in Carl's explanation of inertia, but in the ill-defined, unquantified concept of 'janky' to identify the physical installation characteristics....
However, inertia explains the cameras movements while the building itself is moving:
"The term "inertia" is more properly understood as shorthand for "the principle of inertia" as described by Newton in his First Law of Motion; that an object not subject to any net external force moves at a constant velocity. Thus, an object will continue moving at its current velocity until some force causes its speed or direction to change."
To explain the cameras continued movements after the building stops swaying, the principle of 'impetus' is the explanation (imo):
"When a mover sets a body in motion he implants into it a certain impetus, that is, a certain force enabling a body to move in the direction in which the mover starts it, be it upwards, downwards, sidewards, or in a circle. The implanted impetus increases in the same ratio as the velocity. It is because of this impetus that a stone moves on after the thrower has ceased moving it. But because of the resistance of the air (and also because of the gravity of the stone) which strives to move it in the opposite direction to the motion caused by the impetus, the latter will weaken all the time. Therefore the motion of the stone will be gradually slower, and finally the impetus is so diminished or destroyed that the gravity of the stone prevails and moves the stone towards its natural place."