en_tn_condensed/rev/09/01.md

I saw a star from heaven that had fallen

John saw the star after it had fallen. He did not watch if fall.

the key to the shaft of the bottomless pit

"the key that unlocks the shaft of the bottomless pit"

the shaft of the bottomless pit

Possible meanings are 1) "shaft" is another way of referring to the pit and describes it as long and narrow, or 2) "shaft" refers to the opening of the pit.

the bottomless pit

This is an extremely deep, narrow hole. Possible meanings are 1) the pit has no bottom; it continues to go down further forever or 2) the pit is so deep that it is as if it had no bottom.