dont forget that the prop will fall off if its A not in the right place and B its not done up tight enough.....not that this happend to me or anything..
errm also the prop must go all the way back that it can,
if it does fall off while your moving ..you will hear a noise in the tunnel a loud rattle type noise and also you wont be able to acclerate, well if this happens step on the clutch right away and slow down into a safe spot.
nothing sould be hurt if your pritty quick

all you would have to do would be to put it back on, it normally falls of from the back end.
if the rubbers go, do the same as above then you must replace prop.
if the splines go...if its the female end thats damaged new prop if its other i think you would need gearbox and clutch housing or somthing.
1 good thing to do is make sure every thing is tightened correctly INCLUDING WHEEL NUTS! tire presures bassically every thing they say in retro car magazine to do before a race/track day.
Any way good luck and more importanly have fun!
Cheers
will