"If all the earth was destroyed, would the "death traps" be able to process that many Isbes? I would think that would be a good time for some Isbes the escape."
Earth's destruction does not benefit anyone hence it will never happen. The prison "guards" will never let the livestock dies.
"If there is a net (our prison bars) around this physical earth, then why do other beings come and go out of it and are not trapped by it?"
Every BE IS knowing itself. If i get out i will probably return to help others. Have feeling that i did that already.