General wisdom states that all euphonium solos are either Danny Boy or faster than hell. The end of Napoli certainly fits the bill for the later of those two descriptions. I had the privilege of meeting Lauren when the US Army Field Band and Boston Brass collaborated a few years ago and have been a big fan of both her playing and her blog/travel log ever since. I stumbled on this clip when surfing YouTube and was very impressed. When I hear playing as controlled and effortless as her's I take note and try to apply it to my own playing.
I've played for many audiences as old as the one that she is performing for and I realize how hard it is to make that demographic react that strongly to a performance (including a standing ovation!) But when you play like that anyone and everyone will react.