Ok, taking a step back is a good idea At the end I want a vector that does exactly this what you wrote:

X-SPEED = rotating at 5 degrees per frame.(because abs(X) = 5)
X-DIRECTION = rotating anti-clockwise (because X is a negative number)
Y-SPEED = tilting at 10 degrees per frame.(because abs(Y) = 10)
Y-DIRECTION = tilting clockwise(upwards?) (because Y is a positive number)
Z-SPEED = tilting at 15 degrees per frame.(because abs(Z) = 15)
Z-DIRECTION = rolling clockwise (because Z is a positive number)

(The speed in-space is already done ^^)

Ok, we can get the speed of the rotation (of pan) and we need abs() for that. But the direction of the speed cannot be calculated with this method, because the differents between the pan's can be negative or positive, independently from the direction.