It was an accident, she was drunk, on a load of drugs, but the panic? Who the hell, in a panic, sits in the garage, calls up different friends to help her GET RID OF THE BODY OF A LIVING PERSON, she talked her friend out of calling for help, while the guy was still groaning (she did say she was sorry to him though.
This was way to methodical, she had the body, she briefly, made an attempt to remove him, gave up, got back in the car, drove back to her house, closed the garage door, apoligised, called friends, got one of them, waited till they came, worked out a plan to dispose of the body, waited till he died, then eventually dumped him in a park.
Does that sound like real panic to you?