Hiding From the Obvious

"Hey, bro. Let's go into the gym and watch the chicks work out." Ryan suggested to his best friend.
"Sounds good." Justin kicked up his skateboard and walked into the main gym with him. Lemon air freshener failed at covering the smell of sweat. They sat down on a bench as some blonde twins in their early twenties waved and giggled. Ryan flirted and winked, but Justin's focus zoomed in on a redhead working with her trainer by the weights rack.
***
"Come on, Nina. Pick it up." Mike said as he counted how many burpees she could complete within two minutes. 'And time.' She stood and reached for her water bottle.
"What are you doing? You still have two more rounds to go." Mike said, pulling her back to the mat.
'He never lets me take a break, even for water', Nina thought. 'He's trying to push me as hard as he can.' She walked over to the weight bench and wiped her face with her sweat towel. "Nina, get back over here. You don't get to take a breather. There is no 'breather' in the word 'burpee'." She stepped back onto the mat and he leaned near her. "People are watching you. You don't want to look like a fool to them, do you?"
"No."
"No, what?"
"No, sir." She gritted her teeth. She scanned the gym and caught a glimpse of a clock. 10:45. Fifteen minutes until the session is over. She dropped her eyes and saw a boy of about seventeen years staring at her. He smiled at her while his friend laughed with a group of blondes nearby. 'Why is he watching me?' She wondered. Mike set the timer and she fell back into the excruciating routine of burpees. 'One more round and then a cool-down combo set and then I'm out of here.' Nina smiled at the thought, but that wasn't what her trainer had in mind. "Nina, I feel like you slacked off today, so I'm tacking on another hour and a half. Oblique crunches for a minute, now."
***
'This can't be right. It seems like he's punishing her. She needs a break.' Justin thought with worry. 'What if her body can't take it and she passes out or worse?' He stood and walked to the trainer.
"May I help you?" The trainer questioned while keeping a close eye on the girl.
"Yes, I'd like to know her routine, please?"
"Why?"
"Oh, well, my older sister is looking for a gym that offers a wide variety of workout combinations." Justin said.
"Oh, may I see a photo of this sister?"
Justin didn't appreciate the tone this man had. He never once looked at the stopwatch in his hand, but glanced at the redhead's toned backside in an almost ritualistic manner. And now he wanted to see a photo of his sister, as if his word wasn't good enough? Something wasn't right. Justin thought fast and pulled his phone from his back pocket. "Oh, perfect timing." He smiled and momentarily flashed the screen in . "She just applied for a job at a gym three minutes away from our house. Thank you, though. And, uh, tell Nina to take it easy." He sat back on the bench and smiled at Nina. He knew something about that Mike guy was... off and he was going to figure out what it was.