Revealing mistake: Watch carefully as the statue falls on the bartender. It barely touches his chest and rests on his left thigh. As the bartender slumps dead you can see a wide open gap between his whole upper body and the statue. Even if it crushed his thigh it would not have killed him so quickly. When the bartender slumps down the statue rocks freely as he brushes against it; obviously a styrofoam replica.
Revealing mistake: When the security guard attempts to open the storage room door where the fire has started, he is set ablaze. Look closely, and he is wearing large protective gloves over his hands, plus a special mask. (00:38:15)
Revealing mistake: On the roof during the helicopter rescue scene, there is a panic and some women run to the helicopter trying to land in strong winds. As it explodes, a woman in a slinky dress falls down. Paul Newman helps her up and her dress is whisked up to reveal "stuntwoman" kneepads on her legs. (01:51:15)
Revealing mistake: When Dan Bigelow tries to save himself and his girlfriend from certain death by racing through the flames to get help, watch as he falls to his death. The stuntman portraying him is wearing a protective glove on his right hand. (01:04:40)
Revealing mistake: When Dan Bigelow is going out to get help, at one point you can see him dipping down to get ignited. (01:04:00)
Revealing mistake: When Lorrie throws the chair out the window, follow its path down. It bounces off a mat, revealing that she's about two feet off the ground. (Corrected in the BluRay release). (00:01:00)
Revealing mistake: When Lorrie jumps out of the window, she is replaced by an obvious stuntman: Fireproof gloves appear on her hands, she is wearing a fireproof mask, and her hair is an obvious wig.
Revealing mistake: After Dan Bigelow is killed, Lorrie goes back into the office to protect herself from the flames. When she is kneeling down in the office, you can see the fireproof pants on her legs. (01:05:00)
Revealing mistake: During the party, doors open and a burning man appears. He is wearing fireproof gloves, his face is covered in some dark mask and some sort of awful wig to hide all the safety procedures. He resembles a werewolf. (00:57:20)
Answer: Where the stairs were blown out they could have crossed over to the adjacent stairwell and back.