WATCH: Tenacious Rat Doesn't Want To Leave Old Town Urgent Care

CHICAGO (CBS) -- A very determined rat really didn't want to get kicked out of an urgent care facility in the Old Town neighborhood this weekend.

An employee at Immediate MD Urgent Care at 121 W. North Av. was trying to get rid of a rat through the front door, but the varmint wasn't about to leave willingly.

"I was just so fascinated by its tenacity," said YouTube user kkerans, who posted the video on Sunday.

The rant clung to a broom as the employee tried to sweep it outside, and repeatedly scurried back inside before the door closed, even jumping on the man's scrubs.

Despite the rat's best attempts, the employee finally did manage to get the little bugger out, though it sure looked determined to wait for another chance to get in. Maybe it was just trying to get a flu shot.

It just goes to show, New York might have the biggest rats in the world, but Chicago apparently has the most stubborn rats.

CBS 2's Roseanne Tellez spoke with Carlos Ortega who thinks the Chicago rat is tougher.

"It's fighting off the broom, it's fighting off the door, it's persistent going in. Not even afraid of humans."

Eddie Kamis agrees.

"He's fighting. This guy here is not fighting. He's just delivering pizza," Kamis said.

Back at the scene outside this clinic on North and LaSalle, no comment from the broom wielding man. But a delivery man said rats in the neighborhood live well.