Softly he opened it, swinging it inward an inch at a time, and scarcely breathing as he entered.

It was dark, and there was a second closed door ahead of him.

From beyond that he heard voices.

He closed the outer door so that he would not be betrayed by a current of air or a sound from out of the night.

Then, even more cautiously and slowly, he began to open the second door.
An inch at first, then two inches, three inches--a foot--he worked the door inward.