Here’s a tricky combination to pull off: a workplace romance set in a very dangerous business.

At the heart of “Standoff” are two top-ranked FBI crisis negotiators with a secret: They’re in a relationship, against departmental policy.

Naturally, it’s a case of opposites attracting. Matt (played by Ron Livingston) goes on his gut, while Emily (Rosemarie DeWitt) is an academic who analyzes everything.

It’s no big surprise then that it’s Matt who inadvertently reveals their affair during a tense hostage negotiation. This causes waves among their colleagues, especially their boss, Cheryl Carrera (Gina Torres). But since they’re so good at their jobs, Cheryl can’t afford to separate them professionally.

The show’s fundamental concept is “everything is a negotiation,” and that proves to be the case on “Standoff.” The Crisis Negotiation Unit handles more than just hostage crises, including kidnappings, high-risk suicides, bomb threats, stalking cases and gang violence.

The problem with “Standoff,” created by Craig Silverstein (“The Dead Zone”), is that it’s so uneven in tone. Is it supposed to be a suspenseful thriller, or an adventurous romance? With the two leads at little risk for fear of hurting the romance, the suspense tends to get ratcheted down substantially. Any damage in “Standoff” promises to be collateral.

Still, Livingston and DeWitt have nice chemistry together, and Torres is a plus for any series, even if she’s underused here. But being scheduled opposite the established “The Unit,” “Veronica Mars” and “Law & Order: Criminal Intent,” who’s left to test-drive this hybrid?