A bad Terminator mistake?

in the movie terminator 3,near the end,john,katherin,and arnold(good terminator) go to katherins dads safe to get the codes.the terminator easily opens and takes out the safe door with one hand.but in T2,when they went the cyborg factory place,he never opened the safe.he had to have the kid do it.y didnt he just open himself with his hand like in T3?