in a simple way wat im saying is tht in the bus+man scenario the man runs along wid the bus only as long as the bus continues to move in the same dir in which it was moving when he got down..if it takes a turn etc he wont be running along wid it

or u can say when ppl get off a moving merry-go-round the will run in the tgt direction but along wid the merry-go-round which is rotating.

i hope i make myself cleat