It is not the mast that gets damaged it it the blade cuffs. These are the vulnerable part of the system and must be inspected if the MMI is exceeded. The EC-135 that slide down the hill in the snow shows how fragile that portion of the blade can be. If no MMI is fitted or if it is unserviceable then the a/c has a limit on the slope it can land on. Even so damage can be done if the cyclic is mishandled.