Concealment was impossible.

He uttered a shout that was more like 'Oo goggery bag-wag' than anything else the children had ever heard, and at once brown coppery people leapt out of every hut, and swarmed like ants about the clearing.

There was no time for discussion, and no one wanted to discuss anything, anyhow.
Whether these coppery people were cannibals or not now seemed to matter very little.
Without an instant's hesitation the four children turned and ran back along the forest path; the only pause was Anthea's.

She stood back to let Cyril pass, because he was carrying the Lamb, who screamed with delight.

(He had not whooping-coughed a single once since the carpet landed him on the island.) 'Gee-up, Squirrel; gee-gee,' he shouted, and Cyril did gee-up.