was just trying to help

i regularly check the tyres of my bike for any sharp objects that might have stuck in the rubber and may damage the tube inside while running. have recovered pins, sharp gravels, glass, nail etc.
this morning i parked my bike and just noticed a nail, buried half, in the rear tyre of another bike beside mine. so, with all good intentions, i went and started pulling it out. it was quite thick and used some extra efforts. but i was glad to work to prevent another puncture and a hapless rider!
then, when it was loose enough and about to come out, a faint sssss... sound started. the nail had already punctured the tyre! a late caution thought came up '*stop! this is a tubeless tyre. it won't deflate until the nail is in. leave it. atleast the guy can take it to a punture shop riding. pull the nail out and u'll pull all the air out and he'll be pulling his bike all the way! stop...!' but, as always, it was too late. the piercing had already started hissing and with a very slight tuck, the nail was out. i saw the poor man's bike slowly lowering towards ground, whisling tunelessly. i tried to put back the nasty nail in the hole to plug it but now it wont go in. withing seconds... flat!
no one noticed what i was doing at the rear of a bike in the parking lot. i placed the mighty nail on the seat and... ran for cover!
sorry buddy, was just trying to help!