A seriously injured 12-year-old was left abandoned at a fiery car crash scene by two men, one of whom was carted away from the site in a shopping trolley.
Police said they were later forced to use a stun gun on a dog as they tried to help paramedics treat the injured trolley traveller, who had been barricaded inside a home in Sydney's western suburbs.
The Thursday-night incident in Cranebrook began after a stolen car smashed into a tree and burst into flames shortly before 7.30pm.
The boy, suffering a broken leg and hip injuries, and two men were helped out of the wreck by passers-by.
Before emergency services arrived, one of the men walked from the crash scene while an 18-year-old with a broken leg was taken off by two men using a shopping trolley.
Paramedics were called to a nearby home soon afterwards for that injured man.
They sought police help to force entry to the property to treat the teenager, who could be heard crying out in pain inside.
Acting Inspector Adam Wilson said the home's occupants had barricaded themselves in the property and threatened to set their dogs on anyone who tried to gain access.
One of the officers was bitten as police tried to force entry and a dog was stunned with a Taser.
Two men inside, aged 40 and 55, were sprayed with capsicum spray and arrested, and later charged with hindering police.
The injured 18-year-old was taken to Westmead Hospital for treatment on a broken leg and head lacerations.
He has also undergone mandatory testing.
Both the 12-year-old and the 18-year-old are in serious but stable conditions.
The dog was uninjured and left in the care of a neighbour, police said.
Insp Wilson said investigators were still looking for the car's third occupant and trying to work out who was behind the wheel of the vehicle, which was stolen in the suburb two days earlier.
"They were extremely lucky - it could have been a whole lot worse and far more tragic, particularly when you've got a 12-year-old boy who was ... simply left at the scene by his friends," he said.
The two charged men were given conditional bail and will appear in Penrith Local Court later this month.
