Maybe the inception sound was named differently from the flatline sound and a lua hook was used on player death?
[editline]14th May 2012[/editline]
I found you a hook too
Make customstep.lua (or however you want to call it) inside lua\autorun
local mySound = Sound(“path/to/your/footsteps.wav”)
function GM:PlayerFootstep( ply, pos, foot, sound, volume, rf )
ply:EmitSound(mySound) – Play your footsteps.
return true – If you don’t return (end the function), the engine will proceed to play its own footsteps on top
If it doesn’t work at first, try making another copy of the lua file inside lua\autorun\client.