I was enjoying this great restaurant... it's appetizers, its cocktails/beers... the nice music ... the relaxing atmosphere... when Security and restaurant employees and hostesses informed us of ..."Active Shooter.... Get Down"! We immediately had to dive onto the floor and stay there. After several minutes, we were alerted to get up and follow the security and staff into the back doors of the restaurant and into a more secluded area. There, we waited until a conference room was available and were ushered into this nice room with TV informing us of the tragic events taking place at the Mandalay Bay Hotel and Resort. We were later allowed to leave and return to our rooms only. There was no gambling in the Cosmopolitan's lobby casinos !!!