What is the usage of "is that a start?" here? This is a dialog between off-duty SP with a terrorist bomber from the TV-show "Bodyguard". After "Does it sound OK to you?" he adds "Just talk, is that a start?" - You don't look like you do (will push the button). Listen, the specialist counter-terrorism unit already know about a potential incident on this train. So what I'd like to do is just tell them that you're willing to talk. Does that sound OK to you? Just talk, is that a start? (Talking to the train-guide ) - There's a second bomber but we're talking. Now write this down "Young Asian female, equipped with an explosives vest. Advise SCO19 she's willing to talk."