Kyle Reese was a rightfully scared man. He had an intensity and urgency that a healthy fear can bring out of someone. The hero of The Terminator, a soldier of the post-apocalypse, he’s prone to nightmares of the cold, brutal future he’s been sent from.
He was battle-tested, brave, resourceful and resilient, but don’t confuse courage and cunning for an absence of fear. Kyle was nakedly afraid of what he had to face in order to save Sarah Connor.
Sarah, understandably, was even more terrified of the T-100 (and Kyle, initially), being a civilian stalked and hunted in the middle of the Los Angeles by something even a station full of policemen can’t protect her from. By the second movie, however, that which (barely) failed to kill her has made her stronger. She becomes a hardened survivalist, more fighter than runner, willing to break bones to secure her future, her son’s future, and by extension humankind’s. She is fearsome and fearless during her escape from the hospital… until she once again sets eyes on the thing that hunted her in the first film.