Well, it is surprising, what a bird can take sometimes...
i.e.
https://de.slideshare.net/1st_TSG_Ai...-kiowa-warrior
but on the other hand, to get such a dent in the tailboom means, that it had a considerable movement towards the earth - while the drive shaft for the tail rotor on top of the boom must have experienced a stretching force.
Without checking every flexiable coupling and the correct allignement of the shaft it is quite risky to fly such a bird....
About the dent - just yesterday I saw the last or one of the last episodes of the Mythbusters.
They tried to crunch a tanker train car by heating the inside - closing it up and cooling it down.
It worked nice with cans and fuelbarrels, which they used for miniature testing.
With the real thing - they couldnīt get it to crumble ...
Then they droped a weight on the tanker train to get a dent into it.
After that.....
https://www.youtube.com/watch?v=T9bpUfWy8Wg
That in mind, it was a gamble of russian roulette - this time with an empty chamber while pulling the trigger.....