'Put your shoulder to the wheel.' 'There isn't any wheel,' said the injured Robert, still rubbing his head.
But Cyril had pushed past him to the top stair, and was already shoving his hardest against the stone above.

Of course, it did not give in the least.
'If it's a trap-door--' said Cyril.

And he stopped shoving and began to feel about with his hands.
'Yes, there is a bolt.

I can't move it.' By a happy chance Cyril had in his pocket the oil-can of his father's bicycle; he put the carpet down at the foot of the stairs, and he lay on his back, with his head on the top step and his feet straggling down among his young relations, and he oiled the bolt till the drops of rust and oil fell down on his face.

One even went into his mouth--open, as he panted with the exertion of keeping up this unnatural position.