You’re not counting gravity, and that 40 mph was the horizontal vector, not vertical.
I myself won’t be counting wind resistance, launch angle and terminal velocity, but:
It will take 6.1 seconds to land, and he should land 358 feet out while going 134 miles per hour vertically.
I knew physics class would be useful somehow. :)
Can you run that through the graph program and show the parabolic track, as soon as the void opened, downward motion begins and as you said the horizontal impact distance would be roughly 2/3 of the edge of the clifftop; a sheer drop would put him about 45 feet past the cliffwall in the first second — arcing out to the terminal point.