Math.
40k service ceiling.
40k ft/min = 454mph = 395knots. And that's a straight nosedive from 45k. More than likely that would be at an angle of 30 degrees. Which means lateral velocity would be x3. That means a dive at almost 1200 knots. Mach 2.
45k - 40k descent = 5k to recover....
Lets say they use all 5k and skim 10 ft above the water.
40kft/min = 666.7ft/s / 32ft/s = 21g's That would be spread out over a space of 7 seconds. "ouch"