It was locked.
"I can't rouse him," he said.

"And I did not see him among the passengers." "Nor did I," said Alan.
Captain Rifle fumbled with his master key.
"I think the circumstances permit," he explained.

In a moment he looked up, puzzled.

"The door is locked on the inside, and the key is in the lock." He pounded with his fist on the panel.

He continued to pound until his knuckles were red.