At the end of Saint Saens’ Introduction and Rondo Capriccioso the sixteenth notes go fast and involve big string crossings and shifting and some nicely crazy chromatic business. All that can obscure the fact that there is fun counterpoint going on at the same time. If you listen to the countermelody in the orchestra part, it is an amazing experience. Plus, it will help you sort out all the “technical” problems and prevent you from rushing too.
Try playing this duet version of the ending with another violinist, but play really slowly at first, so you have time to hear what is going on! There is plenty of time to go fast later on.