A brisk, tense, stripped-down thriller set against a chemical attack on Los Angeles, focussing on a woman who was heading into the city as the explosions happened and her husband at home. If the film's central dilemma is pretty predictable from the outset (not least given the title), it's well-executed, the two main performances are good and the short running time is in its favour. It takes on extra resonance this side of a pandemic, and the ending shows some story-telling guts.