Jesus Christ, talk about a plot device. Why wouldn't you (the idiot) just say over the phone? "We don't know who might be listening?" My guy, if they're listening to you, then they heard you planning to meet at the restaurant, and they already know that you know so why wouldn't they just get rid of you as soon as possible? (Surprise surprise, look at what ended up happening.) Like just say the damn thing so at least someone else knows. If you (the author) wanted to do something like this, at least do it in the standard drama way where they're killed on the phone or right before they go on the phone, something like what happens to a certain Mr. Devivie, because at least that makes an amount of sense.