Why missionary to missiologist?

My day has been filled with the study of missiological education. In the text Missiological Education for the Twenty-First Century (Woodbury, Van Engen, Elliston, 1997), I came across the following quote that gives the reason why I am pursuing a PhD in Intercultural Studies, and why I am attempting to move from being a missionary to becoming a missiologist:

Samuel Escobar “The key difference between a missionary and a missiologists is that while the missionary accomplishes the task that his or her call demands, the missiologists also reflects about the task in a critical and systematic way.”

Not only do I want to accomplish missio Dei (the Mission of God), but I want to reflect on WHY I am doing it. 

More to come...thanks for reading.