Lynette Eason 
Code of Ethics (The Cost of Betrayal Collection) [EPUB ebook] 

When Detective Isaac Martinez lands in the ER with a gunshot wound, he pulls through thanks to trauma surgeon Ruthie St. John. But as the witness to a crime and possible corruption, Martinez is at risk from someone intent on silencing him–and those around him–forever. When he barely survives another attack while recovering, both he and Ruthie must flee, trying to outrun deadly killers while locating the evidence they need to end the danger.