Experiencing a sudden sense of danger (7)
I believe the answer is:
alarmed
'experiencing a sudden sense of danger' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for alarmed that I've seen before include "as a door handle may be?" , "Fearful" , "Anxious; disturb" , "Frightened, scared" , "Worried" .)