how dangerous would it be? we have an exclusive look at how terrorists might put explosives in a tube and detonate it in a car or a crowded plane. and hotel horrors. we ll get firsthand accounts from journalists in sochi who say the accommodations deplorable if, if the rooms they booked are ready at all. i m wolf blitzer. you re in the situation room. just hours before the opening ceremony, the olympics in sochi, some u.s. officials i ve talked to are sounding more worried than ever about a possible terror attack. we re told the united states is working with russia and other countries to try to disrupt several possible threats. that s in addition to the new warnings about explosives hidden in toothpaste tubes. and now we re also learning that airline security officials in this country are responding by ordering new flight rules for flights to russia. our correspondents are covering all the troubles in sochi, but