The 16-year-old from Upper Moreland remained in the hospital on Thursday.
So far there is no word of any charges in this case.
The incident happened around 8:30 p.m. Wednesday at the Willow Grove Park Mall in Abington Township, Montgomery County.
Police say the 16-year-old was hanging out with three others when he began to "act oddly."
According to investigators, the teen suddenly sprung out of the car, began running at full speed, then leapt off of the third floor deck of the garage.
Medics transported the teenager to Abington Memorial Hospital with serious injuries.
Because of his age, the teen's name has not been released.