Infiltration

"It's time, researcher 016."

A human man, with a pale and old face, suddenly muttered as he stood up from the furniture in the room he was in.

"Well, do you remember all the entry rules, researcher 698?"

Another man, who looked even older than researcher 689, replied as he also stood up with the help of a cane.

"Of course! The first rule is that we have to make sure that no one follows us. The second is that we have to wear a face-changing mask whenever it's our turn and the third is that we must always follow the routes specified by the organization to ensure that there won't be any infiltrators!"

Researcher 016's eyes narrowed, making his wrinkled face even more unpleasant to look at.

"Are you sure that's all?"

Researcher 689 gulped as he tried to remember everything he had been told in the last few months of training, but he couldn't remember anything else.

"There's nothing else, sir!"