If the timing belt breaks on a 07 Mits Lancer is it likely to cause other damage

It is listed as an 'interference engine'. You can pull the valve cover and look at where the lifters are compared to where they should be.If the engine hasn't been disturbed yet then see where the cam timing is , relative to crank.If it's close to where it's supposed to be , you may be one of the lucky few with no damage to valves. Best way to tell without pulling the head is to put the timing belt on at proper position(patience at turning crank/cam to set up is a must!), and do a compression test ,if after visual inspection while turning it over by hand(with belt on) no valve problems are obvious. Also make sure any issues leading to the CAUSE of the timing belt breaking (oil leak,water pump failure ,idler/tensioner pully wear/failure) are taken care of. good luck.

It depends on if the engine is designed to free reving, if not, the pistons will slap the valves causing major damage. Check the repair manual or call your local auto parts store..

if the timing belt snapped turn engine over to make its not seized if its an interferance engine then might have bent some valves in the head