Quagmire took a double take at the incoming fatmen, there were in fact three of them. He was confused, baffled, and quite possibly bamboozled. He just felt the tremors from the ground just now? When he first fought them, he could feel the tremors from hundreds of meters away from him.
That was not the only thing that got into his mind that confused him, no, not that, but the fact that there were three of them! Having just felt the tremors just now is the equivalent of a fat man getting stealth technologies; why is that, and why is it so advanced?
There are things in the world that he just could not find the answer to, and this one is one of them. There is no absolute way that the flaps of fat that seemed to have a grudge in itself would not sink as it walked and, therefore, make tremors. He guesses that the world really is big.