The suicide must pass as an accident.

He himself must seem to have no knowledge of it.
Morale forbade the admission either of treachery or self-destruction, for any member of the Legion.
The sight of vague, pearl-gray clouds on the far south-east horizon, and of a dim, violet line of peaks notched across the heat-quivering sky in remotest distances, struck him like a blow in the face.

Clouds must mean moisture; some inner, watered plain wholly foreign to the general character of the Arabian Peninsula.

And the peaks must be the Iron Mountains that Rrisa had told him about.

They seemed to rebuff him, to be pointing fingers of accusation at him.