Professor Wood cracked

This post comes in relation to the last. In my previous post I mentioned how stoic professors are in the face of incredible temptation to laugh. Yesterday I was witness as one of my professors folded under the pressure to remain aloof. Yes, she laughed...kind of.
It happened in my Dickins class. (Yes I'm in a class devoted entirely to Charles Dickins.) There's a girl in my class that makes this funky noise every single time class is held. At first you think she's just hiccuping, but then the hiccup increases in volume as well as duration until she's shrieking. The noise that she makes sounds like a mixture of a corpse, post-mortem, gasping for air and the sound that Shiz surely made as he, after he had had his head cut off, "raised up on his hands and fell; and after that he had struggled for breath, he died." (Ether 15:31) Only imagine that sound increased in volume and occuring in the middle of a discussion about the societal criticism made by the masterful pen of Dickins. It's distracting sometimes and hilarious...always. As for what causes this regularly occuring death-rattle, Will, one of my classmates, and I have several theories, but due to their superfluous nature in relation to this story, I shan't share them, unless asked.
Anyway, the first couple of times this happened in class, I grinned broadly and looked at the young lady to see her reaction. She always just sat back in her chair and pretended that nothing had happened. (Be it known that this class is held in a classroom where we students sit in groups around tables. I'm not straining my neck or anything to look around at this girl, she just happens to sit right in my line of sight.) After a while I grew accustomed to this rather noisy ritual, and have more recently been able to keep any visual evidences of my mirth within. This has been one of the occurences of which I spoke in my last post which, to my consternation, has never caused the slightest interruption in my professor's flow of speech; until yesterday.
After making some profound statement about the significance of the bells in Dickins' The Chimes, Professor Wood paused dramatically. Right as this pause was gaining steam and increasing the gravity of what had just been said, the great shrieking gasp was set loose upon the class. It was a virtuosic production. Caught off guard, Professor Wood let out a loud guffaw. I was stunned. She quickly swallowed the guffaw, but by interupting it before it had run its full course she caused a kind of loud thumping noise within her chest. This only increased the hilarity of the situation. She looked horrified. After a lightning-quick glance around the room, Professor Wood gathered herself and continued on with the class discussion. Everyone but Will and myself sat attentively as if nothing had happened. It was astounding. Why was not everyone rolling around on the floor unable to contain their mirth? I was amusedly perplexed. I caught Will's eye and was forced to look away rapidly to avoid a sudden outburst of raucous laughter.
After class had ended Will and I discussed this experience and we came to the conclusion that the rest of our class is peopled with zombies. It's the only possible explanation. How else could they fail to see the humor in the situation? As for Professor Wood, she's given me hope. Perhaps it is permissable for a professor to have a sense of humor; as long as they're willing to fight off the undead.