In Terminator Genisys, Skynet sends a terminator (a T-1000) to 1973 in order to kill Sarah. It is able to kill her parents, but Sarah swims away and runs into a T-800 that was sent back to help her. We see Sarah in the water, under a small wooden bridge, looking up at the T-800. Then we see the T-800 carrying Sarah away to safety.
We never see the T-1000 nor do we find out how it was killed. They are extraordinarily difficult to kill (in 1984 Sarah and the T-800 are able to dispatch one after A LOT of planning and a lot of acid). How did the 1973 T-1000 get destroyed?