In reference to the descend rates mentioned earlier (2000ft/min), this picture
Onderzoeksraad voor Veiligheid is from an EC130 accident investigation report, which mentions a descend rate in excess of 846ft/min & 20+G at impact, down from the max 4500ft/min. reached during the descend. The damage to the windscreen, instrument panel, the whole front cockpit area was due to the crash and not post crash rescue. Engine, gearbox, rotor assembly were largely separated from the hull. Blades fractured.
Worth noting that the tail boom and fenestron were reported to be fairly undamaged, except for a fracture at the root of the tail boom!!
Given the fact that the EC135 was lifted out by the rotor assembly, less structural damage (even after going through the ceiling) can be assumed. So a descend rate on impact below 800ft/min, will be a better estimate. Of course, 15G or even 10G at impact are devastating.