Replying to Terrorist attack on Sochi, could it happen?

Just really confused about how the Russians are running security over there. Several sources claim that its just really chaotic. Even accommodation for athletes and the public are not going well even now. Just imagine when the masses gather and things get really crowded. I've seen pictures and read stories of how bad things are now, and with the games starting in only 2 weeks!? Personally I don't think it looks one bit promising. Just hope they will take some serious precautions.