Derrick Perry, a United States Marine veteran, confronted a knife-wielding man in the parking lot of the Traverse City Walmart.

One of the men who authorities say helped take down a suspect who stabbed eleven people at a Walmart told NBC News about how he sprung into action. Marine veteran Matthew Kolakowski says he took off running after the suspect and rammed him with a grocery cart to prevent him from hurting more people.

Matthew Kolakowski was shopping with his daughter at a Michigan Walmart when he heard screams and saw a man with a knife.