Given the three orders of magnitude on the density of water over air I am amazed the machine did not kick more in the yaw. TR RPM/pitch didn't change instantaneously and the fastest part immersed .... blah blah blah.
The only way to absorb that energy instantaneously, as Crab suggests, is to wind up that TR drive shaft ...
But, being a nerd, I reckon the entrained flow and low pressures would have caused cavitation limiting the lift of the affected tips. For the short durations of impact anyway.
And, as Agile says, if that TR had been going the other way the effect may have (paradoxically) been much worse.
Notwithstanding the noted implications of an abrupt impact of an axisymmetric planar lifting assembly inclusive of a plurality of blades perpendicularly disposed to, and impinging upon, the free surface boundary between atmospheric and a hydrostatic body including, but not limited to, H2O the conclusion is as previously determined by Sikorsky (1939)
et seq ....
.... You Bend It, You Own It!!!