Como Kyle Reese sabia que Sarah Connor estava no técnico?

Reese sabia exatamente onde ela estava, porque ele a estava seguindo de seu apartamento. Seu objetivo era vigiá-la até que ele pudesse detectar o Terminator, então (tente) matá-lo e afastá-la.

She rode off the kickstand and putted slowly down toward the cars. As she passed the dusty gray sedan, she looked in and saw that there was no one there. When she reached the apron, she paused, checking for cross traffic.

If she had looked back, she would have seen someone sitting up in the front seat, slipping his scarred hands on the wheel.

Kyle Reese.

_{^{Terminator: Official Novelisation}}

Note que Reese esperava que, com seu conhecimento de Terminators, ele pudesse matá-lo e ficou surpreso quando ele continuasse chegando, apesar de ele carregar uma espingarda inteira à queima-roupa. Claramente, ele não esperava que a Skynet tivesse enviado um modelo tardio T-800 com todas as guarnições.

He must have been a seven hundred, Reese thought to himself. He stood there for a heartbeat, the adrenaline still pounding through him, making everything seem slower, feeling the rush, as if he were riding on top of the wave.

...

Reese had fired in midair as he leaped from the back of one vinyl-covered booth to the next. He landed agilely and came up firing. He fired again— Die, fucker! — and stroked up another shell. The Remington kept exploding, one blast after another, brutally, savagely, unrelentingly, pushing Terminator backward, toward the plate-glass window.

_{^{Terminator: Official Novelisation}}

Por que ele não fez contato com ela antes, isso é explicado pouco depois

“I had to wait till he moved on you before I zeroed him. I didn’t know what he looked like.” Sarah realized he was referring to the people who were injured or killed at Tech Noir.

_{^{Terminator: Official Novelisation}}

E obviamente ela precisa Vejo um Exterminador do Futuro ou ela simplesmente assume que ele é uma pessoa louca e foge dele.