This is the definition of a heart-stopping flight. When the crew of a Southwest Airlines flight on Sunday discovered a cargo shipment containing a human heart, the flight was forced to turn around. The plane had been en route to Dallas from Seattle when the organ was discovered. It had been left on the plane from a previous flight from Sacramento and was supposed to be offloaded and delivered to a hospital in Seattle before takeoff. Thanks to a baggage mix-up, this never happened. In order to make sure the heart reached the hospital — and ultimately, the intended patient — in time, the pilot made the difficult decision to turn the plane around mid-flight.

Given the life-or-death consequences of the situation, it would be difficult for passengers to get too angry about the course change. Hearts are only usable for transplants within a small window of a few hours, so turning the plane around was an absolute necessity. When the plane landed back in Seattle, however, mechanical issues caused it to be taken out of service, requiring even further delays. At last, after a five-hour total delay, a separate plane was brought in to complete the trip to Dallas.

Southwest Airlines apologized to passengers in a statement. “We sincerely regret the inconvenience to the customers impacted by the delay,” said a spokesperson for the airline, “and we are following up with them with a gesture of goodwill to apologize for the disruption to their travel. Nothing is more important to us than the safety of our customers and the safe delivery of the precious cargo we transport every day.”

H/T: BuzzFeed News