Dani and Rainboe,
The survivability of a crash depends on g forces...and the way these forces are spread at the instant of the crash.
You both concentrate - rightfully - on the stopping distance, but it's only one aspect of what happened.
My opinion - and it's just my opinion - is that the distribution of the deceleration forces played a significant role :
The way I see it
1/ They hit the groung tail first, beginning a structural absorption of said forces (the energy is spent partially in bending the tail and shearing the stabilizer).
2/ With some of the kinetic energy already spent, some is further absorbed by the mud and shearing the landing gears off.
3/ When they hit the ground after a fuselage rotation around the gear struts, the inertia of the different parts of the fuselage, especially those ( the parts of the cabin on both sides of the wing root ) in a cantilever state. The shearing/compressing energy involved broke the fuselage into the three pieces we can see.
4/ the farthest point away from the de-rotation would be the cockpit, also with the greatest deceleration. The part that was subjected to the second most important decel will be the one just abreast of the landing gear...
In other words, the structure deformation/failure absorbed most of the crash energy, which apparently wasn't very important (that's relative...),considering the slow speeds involved.