A mass alert warning Walter Reed National Military Medical Center about the presence of an active shooter on campus was an error, the U.S. Navy assured the public Tuesday afternoon.

But not before the alert — which the Navy said did not include the words “exercise” or “drill”— sent patients sheltering in back rooms to make tearful calls to loved ones and put security personnel and police on high alert.

The Navy said the notification system was accidentally triggered in preparation for an upcoming drill. But Rep. Dutch Ruppersberger is not satisfied with that explanation.

The Maryland Democrat was being treated at the hospital when a lockdown was instituted and sirens started to blare. Ruppersberger said at no point were patients informed the alarm was a drill.

“It was botched. Somebody messed up,” Ruppersberger told the Baltimore Sun. “I’m going to get with the Pentagon and find out how this happened.”

Ruppersberger, who oversees defense spending as a member of the Appropriations Committee, tweeted that patients had been notified there was an active shooter on the premises at 2:30 p.m, sending news organizations scrambling for more information. By 3:35 p.m. he indicated an all-clear had been issued.

He also expressed concern about how those tense minutes affected the military men and women receiving care at the facility when the sirens rang out.

“What bothers me is that you have people with post-traumatic stress, you have people in that hospital who are really hurting and have problems, you have amputees,” Ruppersberger he told the Sun.

1/3 If today’s active shooter investigation at Walter Reed Medical Center was a drill, I clearly did not get the memo and neither did the other people who were told to shelter in place with me, nor did Montgomery County Police and other agencies…

— Dutch Ruppersberger (@Call_Me_Dutch) November 27, 2018

2/3 People were scared and upset. Drills are important and today was a valuable learning experience for me, but training exercises must be properly communicated…

— Dutch Ruppersberger (@Call_Me_Dutch) November 27, 2018

3/3 I will be following up to see what went wrong and how the process can be improved for the future. I’d like to thank law enforcement for their quick and professional response.

— Dutch Ruppersberger (@Call_Me_Dutch) November 27, 2018

Ruppersberger praised service members who barred an unlocked door during the scare.

A hero indeed. I thank him for his service and willingness to sacrifice. https://t.co/U73rGEteOy

— Dutch Ruppersberger (@Call_Me_Dutch) November 27, 2018

He promised to seek answers from the military.

“I will be following up to see what went wrong and how the process can be improved for the future,” he said.

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