Revenge is sweet

"As long as I'm alive," you say.
Mark unlocks your handcuffs and drives to a place which is underground. You find yourself surrounded with other 'recruits' training.
"What am I supposed to do? What is all of this?" you ask.
"It's the training facilit. If you do good enough you can go back to the real world-under certain circumstances. Here's your room. Get yourself cleaned up and meet me at the training facility," he says.
Once you're ready you head to the training facility to find 2 people. 1 girls and 1 guy.
"So you're the newest recruit huh? You think you can make it? Yeah right," says the girl with blonde hair.
"Don't be rude Tiffany. I'm Harris," the guy says.
"Uh..Where's Mark?" you ask.
"Ugh, he should be coming any sec-oh wait he's right there."
"Ok, recruits. Time for your daily exercise. You must denotate a bomb before it explodes," Mark says.
How do you go about this?

You have 2 choices: