Yamino 's switchblade starts to slide into the widening crack , but Anzu saves it . The trap door groans and creaks but it 's opening more and more , a foot at least , before it stops . " Guys , we 're coming for you , " Honda is shouting , now practically sitting on the rod ; Bakura grabs the rod as well and hangs all his weight from it , opening the door a few inches more . It 's getting obvious that they 're going to have to break whatever mechanism is holding the door shut before they can get it any more open . But by now there 's light and - " Is that smoke ?

Question: Why is the narrator and others trying to get the door open ?
Answer: Smoke is nearby .There is a class being held on the other side .There is a switchblade on sale in the next room .There is a crack in the door and they want to see the other side .