I also saw our Maths teacher in 1R at MGS, Bert Rudling, tap the blackboard sharply with what I remember as a rattan pointer. He did this frequently & not as a warning re CP, just to gain attention.
Unfortunately, he did it once too often and the tip end, about 9 inches of the 3 foot flew off. I caught it, otherwise it would have parted my crew-cut, if such a hairdressing feat is possible! Damn good slip catch from a sitting position if I say so myself, even if it was two-handed.
Bertie left after one term though he’d been there 3 years already, but this wasn’t connected with teaching us. I think, as he was the only staff member in a bubble-car, he probably died trapped in his garage. Those things were hard enough to get into, but exiting was infinitely harder!