Nice one Pete! Shades of "bit heaven"!

I don't know where your sneezes go, because mine seldom go anywhere but out!

However, what might be more relevant to the question is the following reflection. A sneeze is not a simple, indivisible action like a twitch, but an example of an innate reflex sequence, that is to say, an complex action consisting of one action leading to  another till the whole show is over.

A clearer example, if you ever have bathed a dog, or watched it as it comes out of water, and seen how it shakes itself, you may have noticed that it begins by shaking its head, then neck, shoulders etc, the whole sequence progressing along the body till the last of the shakes leak out of the end of the tail. But if you are alert, and you grab the head before it gets into its rhythm, and hold it still by force, it kills the whole sequence and the shakes err... go away somewhere. If you miss your cue and do not grab the head before the shakes have progressed as far as the neck, you can do as you please, no matter how rigidly you hold the head, everyone in range gets showered as the shakes progress down the dog.

Similarly, your sneeze begins with an inhalation, and if it doesn't progress properly, the sneeze peters out into snuffles, tickles, and similar frustrations. For waiters carrying whole armfuls of food a sneeze can be a disaster, and for them the trick is to do a quick, nose-and-mouth sniff to interrupt that first catastrophic inhalation.

Feels terrible, but it works if you are quick enough off the mark.

Perhaps your reaction to being addressed by someone as your sneeze builds up is such a sequence breaker.

Gesundheit!

Jon