"Johnny ... Johnny, where are you...."
Helen fainted.
Several other garage-sized beasts converged on her, all looking as hungry as the first. In reality, they weren't hungry—their food consisted of stone, primarily, while they also drew sustenance from cosmic radiation. But they liked to tear things to pieces. They were native to the planetoid; the Vegan Scientists had gathered them up and shoved them through the intraspatial-doorway to this side of the planet, where they wouldn't be underfoot all the time. It was a one-way doorway, through which Pud or Gop would occasionally reach to pluck one of the beasts back for use in experimentation.
Now, just as the beasts reached Helen Gorman, one of Gop's tentacles came through the doorway, followed by one of his smaller heads. The Junior Scientist picked up Helen, and hastily extruded another tentacle from the first to bat aside one of the beasts that leaped after her.
The part of the tentacle bearing Helen Gorman swished back through the doorway. The head and the rest of the tentacle followed.
The beasts commenced fighting among themselves, which was what they did most of the time anyway.
Gop, however, in his haste, had forgotten to repolarize the molecules of his body while retreating through the doorway ... and the moment he cleared the doorway on the other side of the planet, the doorway reversed—still one-way, but now the other way.
And eventually one of the beasts, attracted by all the flickering and flashing and frantic scrabbling visible through the doorway, abandoned the fun of the fight and leaped, like a ten-ton gopher, through the opening.
The others followed, naturally. They always chased and tore apart the first one to cut and run.