In "Back To The Future", after Doc is shot by the Libyans, Marty dives into the DeLorean, unknowingly activates the time circuits and then proceeds to drive round and round the car park of the shopping mall with the Libyans' van chasing him. Why didn't he just drive off down the road to get away?
The film's novelisation suggests that the first turn was prompted by him trying to get to grips with the car's powerful engine, then noticing that he'd reached the barrier. Once he'd made the turn, he then missed the car park exit (while swerving to avoid gunfire) and decided that it would be better to outpace the van inside the car park, hence the second turn.
Marty glanced out the rear-view mirror just as the machine gunner took aim. Swerving wildly, Marty saw the bullets churn up holes in the asphalt to his left and rear, but he had no time to congratulate himself. Ahead was the end of the mall lot, which he was approaching at seventy-five miles an hour. His lights struck the metal guard rail, warning him that in less than two or three seconds he would plunge through the barrier and over a steep abutment. Behind him, the bouncing lights of the black van dogged his every movement.
Marty grabbed the wheel tighter, faked a left turn and, downshifting quickly, spun the car hard to the right. The tires shrieked, kicked gravel into the guard rail and onto the windshield, but held, completing the turn and allowing Marty to roar away from the skidding van. As he did so, he floored the car again, saw the speedometer rise from 50 to 75 in one swift, almost spastic motion. But the Libyan driver was no slouch, either. Despite having less power and maneuverability, he managed to turn around quickly and accelerate to the point where he was barely twenty yards behind the sleek DeLorean.
“O.K.,” Marty whispered. “From here on out, it’s nothing but speed.”
He glanced down at the speedometer as the DeLorean roared past Doc Brown’s immobile body. It read 80. As he passed the step-van, it read 85 and the Libyans showed no sign of quitting.
“All right, you bastards,” Marty hissed. “Let’s see if you can do ninety!” Behind him, machine-gun fire crackled, several bullets landing ahead of him, causing the road to ignite and bits of asphalt to clatter against the hood. Distracted, Marty looked to his right too late. For a split second, he had the ability to turn right, race through the entrance portals and perhaps outrun the van on the highway. That split second was now past. Ahead was the opposite end of the parking lot, another guard rail, and, he now noted, less area in which to turn.