Man, I'm trying to resist the urge to pile on here. This has really been covered pretty well by Akulahawk, Aidey, and everyone else who has posted.
Blunt trauma arrests do not survive. Yes, you can carry on and bring up some anecdotal story of a miracle save that you once heard happened when the stars aligned and it was a full moon on the third Thursday of a month. Overall, this is not a salvageable patient. I have nothing against working a code, and I resent the suggestion that determining a patient is not viable represents any kind of laziness. Don't mistake knowledge and pragmatism for ignorance and laziness.
To suggest that this arrest may have been caused by anything else other than the severe blunt trauma is patently absurd. Healthy 16 YOF was out riding dune buggies when she was ejected at high speed and one fell on top of her, and she is now pulseless, apneic, and asystolic. A leads to B, and looking around for some kind of bizarre zebra makes no sense at all.
Working a non viable code because not doing so would mean "not giving it your all" or "taking away whatever chance they have" shows a huge misunderstanding of what has happened here. This patient (body) no longer has a chance. Quite honestly, they would probably be dead from this injury if they were lying in an OR with a team ready when an ATV fell from the sky and produced these same injuries.