our safety, terrorist attacking on site

One day, at Site-██ 15 people became D-Class. They're in the waiting room, they're like talking. The guard is checking their bags, and suddenly…

“We got reports that there was an explosion in the waiting room. For all D-Classes, please evacuate ASAP!“

A bomb exploded. While D-Class is being evacuated, a second explosion occurs at the eastern security tower and collapses it.

Security is tight as all D-Classes are gathered in the canteen. Suddenly, a third explosion occurred at the helipad and caused a scene in the canteen.

“There were at least 3 explosions. We'll be evacuating you now. SCP will also be rescued, please don't panic and listen to the officers' instructions.“ -intercomms

5 hours later, the evacuation was stopped due to the fourth explosion. Later, it was also said that all SCPs had been evacuated. What do terrorists think? Why are they doing this?