in-surrection relate surrection with surrender thus -in surrection = not to surrender = rebellious
erection ... uprising :P
a rebellion always argue with his head (surr in hindi) Upright (erect)
In+sur (head/ government) + reaction ( action/ rebel), so reaction/ rebel against the head/government.
In Sur (Head) Action i.e. INside SUR (mind) to take ACTION against authority