Don't worry, you will not hurt anything!! Cutting a spike will never kill an orchid. I can't put a photo right now since I have to leave for the airport in 30min.
If you cut at the bottom, cut above the first knode (bump). If you want to try to get a side spike, find the spot where the lowest bloom was, and cut right below that.
__________________ Camille
Completely orchid obsessed and loving every minute of it....