You enter the room just as Chris forcibly drags Dennis back through the window, through which Dennis appears to have been trying to escape. From the attitude of everyone involved, this does not seem to be an uncommon occurrence. Perhaps it's best not to ask about it.
Dennis catches sight of you. "Who are you?" he asks, bewildered.
"A member of the audience," Chris says. "Here to see the show tonight. So we will need a full cast, Dennis."
Dennis looks stricken. "I'm sorry," he tells you. "About the show. I'm going to mess it up."
"The show will be fine," Chris assures you, with a strained smile. "Dennis's nature does cause occasional difficulties, admittedly, but we've planned for every contingency."