Then from the safe again, but now in a low gasp, a pant of relief: "Ah!" The ear might barely catch the sound--it was as of metal sliding in well-oiled grooves, of metal meeting metal in a padded thud.

The massive door swung outward.

Jimmie Dale stood up, easing his cramped muscles, and flirted the sweat beads from his forehead.
After a moment, he knelt again.

There was still the inner door--but that was a minor matter to Jimmie Dale compared with what had gone before.
Stillness once more--a long period of it.

And then again that cough from above--a prolonged paroxysm of it this time that went racketing through the house.
Jimmie Dale, in the act of swinging back the inner door of the safe, paused to listen, and little furrows under his mask gathered on his forehead.