I happened to be spectating the scene while on duty. From my point of view the MTF fired first, missed and forced the Infil to fire back.
Unfortunately I do not have video proof of this and may just be wrong on this view point.
However, thus after confirming the rule with other staff and E11 command and consideration of the player at hand not being new;
Went ahead and issued a warn.
As well, it states in the staff handbook.
"A verbal warning can be given out in response to minor misconduct, and can be used in situations where someone may be new to the server and not fully aware of specific rules."
I took this account and did not consider Daniels a new player; As they are Junior Command and a 3 month member of E11.