Velocity squared equals two times gravity times height.
V^2 = 2gh

Or..if MPL was still moving downwards at a considerable clip at engine cutoff
[perhaps 10m/s?] then use this equation V^2f = V^2i + 2ad
d = h(height)
a = gravity acceleration(g)
V^2i = downward velocity at engine cutoff (squared) = 100(m/s)^2
V^2f = impact velocity (squared)
gravity (acceleration rate) = (4.0 m/s)^2 [roughly Mars surface gravity value]
height = 40 meters.

V^2f = 100 + 2(4)(40) = 420(m/s)^2
Vf = [420]^1/2 = (roughly) 20.5 meters/second [that's close to 45 mph, for American values]

Ever been in a car crashing into a wall at 45 mph?