Chemical warfare and the art of Tippexing houses

"Mould," I say.
"What about it?"
"Don't you think the back bathroom wall is looking a little.... Well.... furry?"
It's true, our houses on this road are woefully inadequately ventilated. If a budgerigar breathes heavily the vapour condenses on a wall or a ceiling and mould starts to prosper there.
I was at a party in a neighbour's house some years back and as I stood in the bathroom in a slightly sozzled but increasingly relieved state, I mildly thought how funky it was for them to paint the bathroom ceiling black. Then I realised it wasn't paint, but the inevitable consequence of bad ventilation, poor landlord interest and two devil-may care tenants who loved taking showers with the windows and doors closed. The ceiling was a mould Amazon. I'll never forget it.
Today, therefore, I stood in an aisle of Dunnes Stores looking for a cleaning product that was unashamedly toxic to all living organisms and which would probably come in a pink or yellow bottle with "Pow!", "Boom!", or "Splat!" printed on it. I chose one that had the words "Mould" and "Kill" in equally-sized letters. The shop assistant put it through the scanner using a pair of tongs. It seemed just what I needed.
At home the instructions mentioned protective gear. I had skin for that. They also said to spray on the surface from a distance of no less than 20 centimetres and to leave on for no more than 2-3 minutes. I took the safety off and rattled off a burst at the enemy.
A small colony of black mould began to turn pale right before my eyes. I dabbed at the spot with a cloth and it swished off into oblivion. Great stuff!
Now feeling less unsure, I doused the back wall good-o with two or three bursts in quick succession. Colourless liquid ran down the wall, leaving barreness behind it. I started to whistle a happy little tune.
I was down at the skirting board, poking at a stubborn strip of black, when I realised how much lighter the room was. The evening autumnal rays were filtering in through the two windows in a very pleasant manner. I rinsed the last of the lower wall then stopped to count the windows. We only had one this morning. Where had the other one come from?
Yes, the mould is gone, though I suppose it might come back. We now also have a new roughly circular window behind the jacks that wasn't there before. It will let out the steam tomorrow, but it will be the devil to get a window-frame for, whatever about glass. I suppose I either rubbed too hard or strayed closer than the recommended 20 cm limit. Or was it the 3 minute limit? Ah well. Accidents happen. Right?