push (at)

[CaseyA]

But the fun was short-lived at Montclair State University's student center on Friday night, where more than 400 residents and others had paid $4 to attend the Phi Beta Sigma fraternity party. When the hall filled, hundreds pushed at the doors. Pushing turned to shoves, shoves brought violence and the unsheathing of knives.

What is the difference between "push" and "push at"?

[Rover_KE]

There's no difference.

[CaseyA]

So "push at" is an archeological relic of the evolution of the English language?