I am very sorry. I only tried to be helpful.
Speed in Newtonian physics seems quite simple - being a subject our mind is well adjusted to. The concept of speed on the quantum level, especially when you start mixing it up with relativity, is not. Along with concepts like causality, spatial...
Okay. So this is a "why" question, is it?
1. What is "electron"?
2. What is "mass" and "energy"?
3. What is "speed"?
Nothing but ideas, really. Mental constructs, mathematical crutches. What you need here is not an answer to your question but a good read on philosophical aspects of physics...