another "and on"

“I just hope it’ll ease up a bit in the next minutes, or else we’ll have to swim to our home from here. Sian? Hey, Sian!”
Sian didn’t react, her whole body taut, her eyes unfocused. Suddenly she started shivering, pressed against her legs, and made silent noises that Stella recognized as squeals of distress, something she hadn’t heard in years now, not since Sian’s first day with her. This shook her to her toes.
“What is it, baby? Are you in pain somewhere? Shh, it’s all right, let me take a look, I won’t hurt you. I promise.”
That was when it happened. One moment Stella was cautiously palpating Sian’s shivering body, her brows drawn together with concentration, the next she was disturbed by a strange awareness of another presence hovering right beside her. Her head snapped up and she looked around, frowning.
“Hello? Someone there?” Startled, she realized that there wasn’t anyone or anything as far as she could see along the way. Only trees and leaves. But why did she feel this ominous presence, then? She couldn’t hear anything, either, not even the song of a bird, much less than the sound of steps. Sian had probably felt the same thing, judging from her behavior, so she wasn’t losing her mind. Could there be a rational explanation? Probably not. This started to scare her more by the moment, especially when it seemed that the presence was moving around her.
“Don’t panic now, Stella, it will be all right.” Stella didn’t care that she was talking to herself. The alternative was starting to shriek… It helped, that was the point. However, just as she murmured this, she sensed the presence fading away gradually, until she didn’t feel a trace of it anymore. Almost at the same time, Sian calmed down, the tension easing from her limbs, and stopped making those terrible noises. Yet Stella couldn’t stop shivering, however much she wanted to do so. It took her a few moments to recollect her wits. At last, she said, her voice shaking badly, “Whew, that was kind of creepy! C’mon, let’s forget about getting wet and go home. I need a cup of coffee now. Make that a double espresso, a hot shower, oh, and perhaps an appointment with a shrink!” They walked on, Stella turning every five seconds, still feeling very uneasy, the memory of the happenings being too fresh. In the end, she gained more speed, until she was running, with Sian at her side. She didn’t feel like she was being followed, but one never knew. A lot of things around there didn’t make sense. The goose pimples all over her body didn’t vanish. She didn’t dare to look back again.