Whoa! Gunfire ripped through a neighborhood grocery in the early morning hours, shattering windows as people screamed — and shopper Keanu Reeves reacted like it was a live-ammo version of “The Matrix”! The action star hit the deck, yelling at panicked customers: “GET DOWN!” Everyone stayed plastered to the floor . . . and the gunshots finally subsided.

Warning everyone to stay under cover, Keanu crept to the front of the store and sneaked a look outside. After scanning the empty street, he told the store owner, “Call the police!” Moments later, cops arrived and swarmed the area — but found no culprits.

When they finally declared an all-clear, dazed customers made their way outside and were shocked to find several of their cars had been shot up — a seemingly random attack police theorized was a drive-by shooting by a wanna-be gang member trying to “prove” himself. After helping cops calm everyone down, Keanu collected his groceries and left the scene.