Stop "Random Point in Bounding Box" to return Negavtive values on X,Y,Z direction

I may not fully understand what you’re trying to achieve but you probably do not want to adjust X,Y as you’ll be introducing a horizontal offset that would push the results off-centre.

You could use the ABS like so:

As ThompsonN13 mentioned in his suggestion, you can right click the vector pin and split it; this will give you access to the elements that make the vector.