When gunshots rang out through Strathmore University in Nairobi Monday, students believed they were under siege. They thought immediately of Garissa, another Kenyan university, where a terrorist attack left 148 dead in April.

No voice appeared over the intercom to say, “This is a drill” — even though that’s exactly what it was.

Instead, students and staff at the school frantically tried to escape. They waded through the neighboring Mbagathi River, climbed out of windows and hovered over perches on the side of the university building, looking for a way out. Esther Kindambi, a 33-year-old employee, jumped from the third floor and died.

Some 30 additional people were injured, police officials said during a press conference Tuesday morning.

Strathmore communication director Betty Ngala confirmed the death to The Washington Post over the phone. In a statement, the university said an “approved safety and security simulation drill” had been carried out to test the readiness of the school and their emergency team for an attack.

“In preparation for this, teams of security marshals comprising of staff and students together with the emergency response team were trained on evacuation, assembly points and exit points,” the statement said. “Unfortunately some students and staff panicked and got injured.”

Ngala told The Star, a Kenyan newspaper, that only rubber bullets were used during the drill.

For those on campus, however, the shots fired into the air by unidentified gunmen sounded terrifyingly real.

“I ran into a classroom, but the gunshots still intensified,” a student told The Star. “I jumped through the window and saw some of my colleagues also trying to jump in the same manner.”

Another said he had called his parents to tell them, “Our school is under attack.”

The event followed a slew of security drills at Kenyan universities after the Garissa attack. According to The Star, the latest test was performed at Kenyatta University, where six students were injured and admitted to the hospital.

Real terrorism incidents in Kenya are also on the rise, as the country has been the target of attacks from the Islamist militant group al-Shabab. Kenyan security forces have been criticized for being slow to respond to warnings and reports of such attacks, which may explain Strathmore’s adherence to authenticity in this case.

The university’s statement said: “We have started an intensive assessment of key lessons learnt during this simulation. We will reveal these to the necessary authorities.”

Ugandan journalist Charles Onyango-Obbo had a choice metaphor for the outcome of the drill.

Another Twitter user likened the simulation to “crashing an actual plane with passengers then claiming it was only 1000 feet high.”

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