Continuity mistake: As Sgt. Saunders and Pvt. Stevens are about to enter the HQ, in the close up shots are several soldiers walking out of the HQ towards them. In the long shot of Saunders and Stevens the soldiers have disappeared.
Actor Vic Morrow used a non-firing wooden replica of a Tompson submachine gun due to its lighter weight, thus being easier to carry. He used a heavier blank-firing model when it was required to be fired.