Thanks for the link, Ray. An amusing and nice-looking little video, although Welles was still relatively slim at the time of WOTW. It wasn't until the 1950's that he started to lose the weight battle for good.
John, I agree with Roger that the apology was scripted, and part of the gag. Inducing panic was the whole point of the show, and Welles later said it was only the magnitude of the panic that surprised him. That scripting of the post show banter probably holds true for all the Mercury radio shows. The west coast CHRISTMAS CAROL you graciously provided, for example, has the same closing conversational lines about which Barrymore played Tiny Tim, etc.; just delivered in a slightly different manner. My impression is that Welles left little to chance on his radio programs- with the exception of the OW ALMANAC show of 1943, where his obvious and awkward attempts at comedic ad-libbing are often painful to listen to. But that discipline on Welles's other series is probably a major reason why so many of them still hold up so well.