Red-Blue continued his gnawing at the one spot of the cage.  It had not been with any real intent or plan, at the beginning, but he was beginning to have a purpose.  He had broken through, in one tiny spot, and could feel the outside air.  He attacked the polymer with his teeth with renewed energy.

The polymer had been tested and confirmed as "rodent-proof" before being used for this purpose, of course.  The problem with the test was, that it was on sane, purposeful, reasonably well-fed and goal-directed rats.  Red-Blue, had he been like that, would have determined after a few unsuccessful initial attempts to gnaw on it, that it was too hard and too smooth to give a purchase for his teeth, and given up.  But he had continued, obsessively, without any purpose, to gnaw at this spot, until it became rougher and easier to attack.  He gnawed, he gnawed, and then once he realized that there was the scent of air from outside the cage coming in, he realized in his tiny brain that he did have a purpose.

Well, it was not exactly like that.  Red-Blue did not introspect about his own mental state, particularly, to note that he had been without purpose before, but now had one.  Purpose he had, however, and he attacked it with redoubled energy.  Hour after hour, his ever-growing, ever-gnawing teeth ground away at the spot, until it was, he was certain, big enough.  If the whiskers fit, the head would fit; if the head fit, the body could follow.  He gave a quick glance behind him to make sure no one was preparing to attack him.  He could get through the hole, but it might take a bit of time, and in the process he would be defenseless.  He did not introspect, but he could think ahead well enough to think about that.

He squeezed his head through, wriggled, writhed, and then one of his front legs was through, and he could use it to push against the outside of the cage.  He was well-fed, and a bit chubby, but the fat squeezed through, millimeter by millimeter.  Both front legs were through, and he pushed harder.  His hind legs were no longer able to touch the ground inside the cage; he pushed himself forward with his front legs.  For a moment he was almost stuck again, when his front legs could no longer push against the outside of the cage because he had gone too far through, but his back legs were not able to touch the ground, but also not through the hole yet.  His nose twitched rapidly, and he looked around nervously.  He was utterly exposed, unable to run or fight if anything came for him.  He scraped against the smooth, hard surface of the floor outside the cage, making almost no progress.

Almost no progress, however, is not the same as no progress.  Slowly, but steadily, he moved his torso through the hole, and then one of his back legs was through, and able to push against the outside of the cage.  The other leg came through, and the tail quickly followed.  He looked back, and saw Green-Red on the inside, sniffing at the hole, up on his hind legs to look through it, testing its size with his whiskers.

Then Green-Red began to gnaw on it, to slightly enlarge it so he could fit through it more easily, but Red-Blue had turned away, and was searching for a hiding place.  The room had several other boxes and crates, with space between them and the walls; Red-Blue felt the low-level anxiety which had been with him for several days straight, ever since too many rats had been crowded together into the single cage, begin to subside.  He still heard and smelled several others of his kind, but they weren't packed close around him on all sides, and he felt much better.  As the minutes went by, he heard the sounds of more and more other rats moving about the room.

When they heard the door open, they all instinctively went quiet.  Red-Blue quickly began moving towards the open door, while still staying out of sight of the humans who had entered.  Then, he heard one of them utter a profanity or three.  He of course did not know them to be profanities, as he did not understand the concept of human language.  However, while other mammalian species do not have languages with nouns (except a very few like "predator!" and "friend!"), verbs (except a very few like "quiet down" or "back off"), adjectives, prepositions, and so forth, they all have exclamations that fulfill the same purpose as profanity does for humans.  He also had enough experience with humans to recognize the sound, or at least the tone, and immediately abandoned stealth and begin running down the hallway, looking for any other place to hide.

When he found the spiral slope downwards, and descended to the underground passageway with pipes and conduit on both sides of it, he knew he was free.  There were many, many places to hide here, to stay hidden, and even to sleep.  Now, all he needed was to find a source of food.