Adriana Lima -- So A Model Walks Into a Bar ... [EXCRUCIATING VIDEO]

Mirrors are usually Adriana Lima's best friend, but this afternoon in New York City ... they were her mortal enemy.

Lima was shooting a Maybelline commercial in SoHo Tuesday as she walked around her trailer to get to the door ... all while a gaggle of photogs snapped away.

As Lima turned the corner, she ran SMACK into the bus mirror and hit the ground like a ton of bricks. Or, considering Lima is a supermodel, more like 90 pounds of bricks.