Read it through once

Archer had the nocturnal perspective of Fifth Avenue almost to himself. At that hour most people were indoors, dressing for dinner; and he was secretly glad that Ellen's exit was likely to be unobserved. As the thought passed through his mind the door opened, and she came out. Behind her was a faint light, such as might have been carried down the stairs to show her the way. She turned to say a word to some one; then the door closed, and she came down the steps.