It happened on Southern Boulevard and East 149th Street in the Longwood section.
Police say the suspect ran into the business and took a swing at the victim but missed. He then swung a second time, slashing him in the left arm with a sharp object.
The man then ran back outside and hopped into a dark-colored BMW that fled the scene.
The victim was taken to Lincoln Hospital with a non life-threatening injury.
The FDNY says three other people were transported to the hospital with unknown injuries.
It is believed the suspect and victim know each other, and sources tell Eyewitness News this is an ongoing dispute over money.
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