Those who take it become aware of goings-on under the surface (6)
I believe the answer is:
plunge
'surface' is the definition.
The answer and definition can be both to do with contact as well as being verbs in their base form.
Perhaps they are linked in a way I don't understand?
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for plunge that I've seen before include "land in water" , "Dive quickly" , "Sudden fall" , "Sudden drop" , "Dive or throw into" .)