What is the theme of the following

"sunday at the water park"

“yeah, the job is pretty boring,” mariah admitted, looking at the wave pool from atop her lifeguard station. “but i get to be outdoors and i can go on all the rides for free when i’m done.”
her questioner—berry, a classmate she didn’t know well, who happened to be a customer as well as being the annoying editor of the school newspaper—stretched his arm up toward her in some weird kind of salute. actually he was recording her with the purple-and-black striped phone in his hand. “how are the working conditions? ” he inquired in the important tones of an anchorman.
“they’re—” she stopped cold. she stood up, staring at the crowd who rose and fell and squealed with each new surge of machine-churned water. amid the bobbing figures, she had seen one stop moving, and seen its head sink halfway under the water and stay there.
she grabbed the rescue tube and dove into the pool. in what felt like an instant, she had swum to the far end, a few feet from the wave machine, and stopped behind the eight-year-old boy who was floating face-down. she thrust the long, red foam rescue tube at him. then, she stood in the three-foot deep water and scooped him around the waist. as she lifted his head, a waterfall of clear, bubbly water streamed down. she wrapped both his small, soft hands around the flotation tube and towed him to the side of the pool. she hoisted him high and set him on the brightly painted white cement, then boosted herself up after him.
the boy—his name turned out to be peter—hadn’t fully lost consciousness, so he didn’t need cpr. after a couple of slaps on the back, he was coughing wetly and breathing well, though too stunned even to ask what had happened.
by now, the waders in the pool understood vaguely what had happened. they looked around and asked each other bewildered questions. no one had noticed that peter was drowning, not even the adults three feet away from him. peter’s teenage brother and his friends had sloshed as quickly as they could to poolside. in five minutes, the ems ambulance arrived to take peter to the nearby clinic.
“i got it all on video! ” berry exclaimed. “now give me an interview! ”
she couldn’t give him much of an interview, because the event had lasted only thirty seconds. she hadn’t consciously decided how to act, and didn’t remember many details. her reflexes had done it all automatically. her lifesaving courses had worked!
she hardly knew what she was saying during the interview, and assumed she must sound incredibly dumb and out of breath. later her family and neighbors told her how poised and in-charge she’d appeared. the strange thing was, she didn’t feel as if she’d done anything special. the only thing that felt new was the way she couldn’t keep herself from smiling at everything—at the trees in her backyard, at silly tv shows, at her younger brother, at the table setting at dinner, at