The unnamed couple have dementia and Alzheimer’s disease respectively. They successfully figured out the door code and walked out of the facility in Lebanon, Tennessee. They were found by a stranger about 30 minutes later and returned to the home. They were not harmed during the short excursion, which occurred on March 2.

The man later explained that he had “previously worked with Morse code in the military” and had used that experience to decipher the code to open the door leave, according to a report from the Tennessee Board For Licensing Health Care Facilities.

The facility in question, Elmcroft of Lebanon, has been fined $2,000 following the incident and has changed all the codes for its exits.

“The safety of our residents is the top priority at our senior living community. We are thankful both residents were returned to the community safely,” Elmcroft said in a statement to The Tennessean.

“We reported the situation to the state and their family immediately after it happened and fully cooperated with the state during its review.”

The Tennessee Board For Licensing Health Care Facilities’ report, published on April 7, described the couple’s brief escape from the Elmcroft as an “elopement” and recounted the residents’ explanation.

“Resident #1 stated that he was able to listen to the code when staff punched in the numbers and was able to figure out the number for the numeric to exit the memory care unit,” the report said.

The man had reportedly “exhibited wandering behaviors” in the past but that was not the case for his wife, whose file “contained no documentation of attempted elopements.”

The care facility will now schedule “walking time outside the facility with a staff member present” for the man in order to “decrease these exit-seeking behaviors.” His daughter is also taking him out of Elmcroft more regularly.

Morse code is named after Samuel Morse, who invented the telegraph. It is a method of encoding text in a series of dots and dashes that can be communicated through sound or using light. It was once a common and very important method of transmitting messages but has fallen out of favor in the age of personal telephones and computers. The most famous Morse code sequence is probably SOS, a distress call.

Newsweek has asked Elmcroft of Lebanon, Tennessee for comment.