In A Heartbeat by RJ Nolan

Veteran police officer Sam McKenna has no trouble facing down criminals on a daily basis but breaks out in a sweat at the mere mention of commitment. A recent failed relationship strengthens her resolve to stick with her trademark no-strings-attached affairs. Dr. Riley Connolly, a successful trauma surgeon, has spent her whole life trying to measure up to her family's expectations. And that includes hiding her sexuality from them. When a routine call sends Sam to the hospital where Riley works, the two women are hurtled into a life-and-death situation. The incident binds them together. But can there be any future for a commitment-phobic cop and a closeted, workaholic doctor?