If you are talking about c_move, it is a combination of the two vectors being used to move the entity.
So the .x portion of the first vector (reldist) added to the .x portion of the second vector (absdist) would give you the total forward speed of the entity.

Then you would create three public variables, one for forward, one for side to side movement, and one for up/down movement.

Just after your c_move event, you can assign those variables like this:

c_move(my,my_move,nullvector,IGNORE_MODELS);
my_forward = my_move.x;
my_side = my_move.y;
my_up = my_move.z;

if you are using an absolute speed vector (like wind_speed or some other external factor) you could add this as well.

c_move(my,my_move,wind_speed,IGNORE_MODELS);
my_forward = my_move.x + wind_speed.x;
my_side = my_move.y + wind_speed.y;
my_up = my_move.z + wind_speed.z;

Then use these three variables to access the speed of the object in question.

There are probably other more efficient ways to do this, but this should work, and I don't think it will cause any kind of problem with memory.