The helo lands on the roof of the hospital just as it runs out of gas. Since there was no refueling station there, it would remain there disabled until enough fuel could be brought to the roof to get it airborne again- an arduous task that would involve 55 gallon drums and a hand pump. Despite this set of facts, it is shown a short time later at the main base.
The man driving the Volvo wagon ("Deer Guy") hits a deer and it is thrown into the windshield. The car stops in the road without hitting anything else. He subsequently dies at the scene from injuries sustained in the crash. There is no way a lightweight deer would cause the injuries he sustained. They were more akin to the car running into a heavy or fixed object such as another vehicle or a wall.
Marisa lands the helo at the hospital just as it runs out of fuel. She violated federal air regulations that requires pilots to operate a civil aircraft with enough fuel to complete the flight and land with enough fuel for 45 minutes of normal cruise. While medics in the series have been shown to be disciplined for various infractions no action was taken here for a very serious FAA violation.
It was said that a deer would not cause a death or destruction to a car and kill a person driving.well let facts tell you it is as factual as it can be as a deer's weight appropriately 18stone, double that accompanied by a speed of 50mph the actual speed the deer hit the car was 100mph, and an automatic slamming of brakes is an auto response at the 1st bang hence the car halted after a few feet.