"Tell me again!" The doctor asks.

"They are gone. Both of them." His assistant says again.

"But how?"

A man enters the laboratory office carrying a small cannister.

"I suggest they have been taken by the same people who managed to get in and release these things." The security officer says, holding the cannister up.

"What is it?" The doctor asks.

"Gas cannister. They used a number of these to fake the fire so they could get something out."

"The test subjects." Breaks in the assistant, her eyes opening with horror. "They must have wanted to free our subjects."

The doctor turns to a large glass cage. In it are rats furiously copulating.

"Oh my God! If they have any sexual contact outside..." His face turns an even more ghastly shade of grey...