In one instant he had whisked in at the open door and hidden behind the wall and only in the nick of time; they had already reached the landing.
Then they turned and went on up to the fourth floor, talking loudly.

He waited, went out on tiptoe and ran down the stairs.
No one was on the stairs, nor in the gateway.

He passed quickly through the gateway and turned to the left in the street.
He knew, he knew perfectly well that at that moment they were at the flat, that they were greatly astonished at finding it unlocked, as the door had just been fastened, that by now they were looking at the bodies, that before another minute had passed they would guess and completely realise that the murderer had just been there, and had succeeded in hiding somewhere, slipping by them and escaping.

They would guess most likely that he had been in the empty flat, while they were going upstairs.

And meanwhile he dared not quicken his pace much, though the next turning was still nearly a hundred yards away.