Territorial Army containing such panic? (5)
I believe the answer is:
alarm
'panic?' is the definition.
(alarm can mean panic or fear)
'territorial army containing' is the wordplay.
'containing' says the answer is hidden in the clue.
'ALARM' is hidden within 'territorial army'.
'such' is the link.
(Other definitions for alarm that I've seen before include "Mild panic" , "Arouse to a sense of danger" , "Device to signal danger" , "Alternative to reveille" , "Panicky arousal" .)