Liars can be super calm. This is especially true if they are psychopaths, sociopaths, or are simply lacking empathy for a certain segment of the population. Example: I don't think that Russia is 100% populated by psychopaths or sociopaths, but there is still a huge segment of the population that has 0 empathy for anyone non-Russian. Especially, right now, Ukrainians. Liars can also be excitable. A certain party in Germany in the early 20th century had a figurehead that would shout at crowds to get them riled up and excited. People telling the truth can get worked up, especially if they perceive that people aren't believing them. Especially if someone is attempting to gaslight them. Or they're recounting a traumatic event. Someone who has just been through a bank robbery or a plane crash may get extremely hysterical. People telling the truth can be calm. They've got a PowerPoint presentation that shows all the facts and now they must present it. Calmness (or lack thereof) has little bearing on whether someone is telling the truth or not.