When John is talking to a fellow Military School cadet on the firing range, just before Martin Bedell shows up, John's yellow goggles are on his head, then on his nose, and then on his head again.
When John is helping the other soldier to clear a jam in his weapon, red tape appears and disappears on the bottom of the magazine in the weapon between shots.
The Terminator sent to kill Martin Bedell used the phone book to track down the three Martin Bedells. But the second one is a young child. His name would not be in the phone book, but his parents' names would be. So, unless the boy Martin Bedell and his father had the same name, the Terminator would not be able to find this Martin Bedell's address by using the phone book.
In military training you never load anyone's weapon but your own. You never hand anybody, anything, but a "cleared" weapon.
Young Martin Bedell seems too calm for someone who was almost killed by a strange man and kidnapped by two women from his home. A child his age would be very upset, wanting to know what is happening, and crying for his parents. Yet, he never does and takes it all in stride and is only upset about a late book report. In addition, Martin knows where their house is, yet later when he is sent back home there is no follow up with the police or FBI trying to find who held him and where.
James Ellison says "nukular" instead of "nuclear".
Derek is wearing the lieutenant insignia incorrectly and it is placed differently in different scenes. The bar is supposed to be parallel to the button of the collar. In one scene it is pointed toward the tip of the collar. In another scene it is placed diagonal to the tip of the collar.
When Triple-Eight Terminator was going after Martin Bedell and John Conners jumps and yells to 888 that he is John Conners then the Triple-Eight Terminator takes out after John.
The Triple-Eight Terminator was sent to kill all of the Bedells it wouldn't go after John.