Shadowlair is a novella of 30,000 words (roughly 100 pages), and is only available when you sign up for the TW Iain newsletter.
The crew never returned.
The rescue mission found their abandoned craft a few days later, but a storm forced them to abandon the search.
And so they never found evidence of the stowaway. They never followed the trail into the gully. They never discovered if the crew lived or died.
Or if something worse happened.