Depends on the personality, really. Some people can be outwardly extremely calm in stressful situations. This is not necessarily an indicator of their actual mental state. If he's able to post something on the internet, chances are he's found a way to fend off the zeds for a while and is currently essentially enjoying the peace before the storm.
However, you might want to work on your tone. Try to sound a bit more melancholic, like you know you're going to die sooner or later, hopefully later. When you say "talk to you later", say it like you don't really mean it. Y'know, all that stuff about being fully aware that it might be the last time talking to someone.
A thought for a later episode (or whatever you want to call it): How about having a friend knock on the door strongly, like a zombie is trying to break in? You could curse and rush off in the middle of the video, perhaps with gunshots in the background, and come back after some ten seconds of silence. Perhaps saying you don't have time to continue recording right now.
