Without knowing the context or hearing your director's request, my thought is that he's looking for an emotional sound that will supplement the practical sound of the body hitting the floor, ie. a "stinger" or something that will provoke a reaction from the audience.
Is that what the director is getting at? Or is the sound supposed to be some other type of ...
If you're in some kind of educational environment, college etc, then use what everybody else uses, or what the teacher/lecturer uses. That way you're only learning sound design, not also an entirely different interface & methodology.
If you're working solo, then there is no "best" only the one you're comfortable with.
I've always used Cubase/Nuendo, ...
If you end up using Qlab, and want to ad an interactive element to your show, try an ICubeX digitizer and some sensors:
It might help you find something new and interesting to do with sound design.