Rumour as in myth?
Guys - please get your infos right, or I ll have to book mark pprune under 'spam'.
Uncontained APU failure on takeoff. Debris took out two hydraulic systems plus some air duct plumbing which later on caused the smoke.
The idiot who got injured was a pissed up brit (yeah - I know: stereotype) who despite cabin crew warnings made his way to the loo during takeoff.
After they patched him up and a sobering nap, he claims he wanted to warn crew because he heard 'noises'.