"Rats?" Penn inquired. He wondered where the gas mask wearing woman got that idea from, and shook his head at her. This wasn't some bunker where he lured in special people with masks, only to turn them inside out to see how they all ticked in different ways compared to one another. He wasn't some mad scientist, willing to rip everyone to pieces to see how the human body worked. He was a scientist and a researcher who wanted answers, but not with a 'whatever the cost' mindset. 

"To me, all of us are keys to the puzzle. I'm not going to turn you inside out for answers, and everything I ask of you is entirely optional. You can leave whenever you please, and come back just the same." he told them all, but his words were directed more at Charlotte than anyone else. "I'm not going to force you to stay, nor foce you to be tested upon. The best results come from a willing subject, and don't worry about anything inhumane happening here. I can assure you all, that numerous safety measures have been taken make sure that everyone here is in a perfectly safe environment"