In Discretion - Ylendrian Empire universe, #1

Thanson Nez thought his career as a Discretionary would take him to the stars, not strand him on a space station at the ass-end of the Empire. Thanks to his last client, he's carrying a secret he can't get rid of fast enough, but his oath to the guild means a swift, painful death if he shares it. Already desperate for help, he runs into yet more trouble: his ex, and an explosion that paralyzes the station moments after their uncomfortable reunion.
Kazra Ferdow, Station 43's communications officer, is almost as blindsided by the return of his first love as he is by the sudden loss of power and life support. The station is a floating graveyard in the making, and something is turning its inhabitants into savage killers. Fighting human monsters and damaged tech, Kazra and Thanson must put aside their past long enough to try to save everyone. The more light they shine into dark corners, the more Thanson realizes how many people might die for the secrets locked in his head-and what he's willing to sacrifice to make sure Kazra isn't one of them.