During My military time I took the EIB test (expert infantrymans badge)
As I recall you dont have to take down the bolt assembly to do a feild strip!!
So she prolly would have been done in 30 seconds or so
Proper functions check for M16 a2; Charge, select safe , select semi pull trigger and hold, charge ,release trigger, pull trigger,( complete cycle of semi firing) charge, select burst, pull trigger and hold, charge 3 times, release trigger, (complete cycle of burst fire)