How to proceed with bike damage within 100km of having a service

[eala]

If you have noticed how often chains come of in professional cycling races then this can happen to anyone if shifting is also not done correctly . My wife is a good car driver but her left front tires of her car lasts have the time mine does because she accelerates through a turn where i let the momentum do it for me .If you are new to cycling and shift from the big to the small front ring with the chain on the largest cog on the cassette the momentum of the chain moves inward and the chain can end up in that space .I am just stating that there is a good and not so good way to shift gears