Miss, can you come now only there's a boy on the floor and he's not breathing." Rush next door to see shocked supply teacher pointing at pupil on floor clutching chest.
I can't decide who looks paler - the boy, him or me. Begin first aid (why, oh why isn't this taught to all student teachers?) and send for the nurse.
A message comes back that nurse is a bit busy right now and can it wait?
"No, it bloody well can't - boy not breathing, need ambulance," I scribble in capital letters, underlined, on a scrap of paper and send back. Dial ambulance on mobile.
Eventually return to own lesson and carry on. No offer of relief or a break. Just the expectation that regardless of the medical emergency we will soldier on regardless. Some days it's more like an episode of Holby City with 42 pupils visiting the medical room in a single day.
Nurofen Plus, Beecham's powders, vitamin C and echinacea tablets should be offered free to ward off the infections that spread as a result of being in overheated, unventilated spaces with 30 adolescents for hours on end.
Even the holidays bring no respite. The constant summer headaches I suffered were, my chiropractor informed me, due to a change in routine. I had stopped hunching up my shoulders and was missing the adrenaline rush of being in a constant state of red alert. I was also sitting down.
Ring in at 6.03am to explain to deputy head that I have pneumonia and won't be in. She is already at her desk primed and ready to go. She hasn't been off ill in 10 years. Despite the delirium of the infection I am expected to set cover work and dictate it over the phone.
The boys make me get-well cards featuring germs being blasted to smithereens by guns. The girls' cards are sparkly and pink with glitter and hearts.
Upon return my room looks fine. Then I discover that someone has squashed cheese sandwiches into the spider plants and the stationery has disappeared. The balls of the computer mice have also been nicked, the legs of the table unscrewed so that it collapses when I put my bag on it and the overhead projector mirror has lipstick kisses on it.
My colleague has had bronchitis. On our return to work we hear one another coughing through the walls.
"My grandad died of pneumonia - will you die too, Miss?" They sit transfixed in case I pop off during the lesson and spare us all the boredom of the literacy strategy.