Run in for

“Not a word to Molly,” he whispered to Harry as he opened the. trunk and showed him how it had been magically expanded so that the luggage fitted easily.

When at last they were all in the car, Mrs. Weasley glanced into the back seat, where Harry, Ron, Fred, George, and Percy were all sitting comfortably side by side, and said, “Muggles do know more than we give them credit for, don’t they?” She and Ginny got into the front seat, which had been stretched so that it resembled a park bench. “I mean, you’d never know it was this roomy from the outside, would you?”

Mr. Weasley started up the engine and they trundled out of the yard, Harry turning back for a last look at the house. He barely had time to wonder when he’d see it again when they were back. George had forgotten his box of Filibuster fireworks. Five minutes after that, they skidded to a halt in the yard so that Fred could run in for his broomstick. They had almost reached the highway when Ginny shrieked that she’d left her diary. By the time she had clambered back into the car, they were running very late, and tempers were running high.

What does 'run in for' mean here?