Acquiring the Soul Sphere on Doom 64 level 32, Hectic:

(Note: For a video demonstration of the walkthrough below,
click here.)

The Soul Sphere sits in a small chamber, the floor of which
will drop down as the Soul Sphere is taken, creating a low,
square pit.  A player inside this pit cannot escape.

It is possible, however, to take the Soul Sphere and remain
standing at the very edge of the pit.  This is a difficult
task since the game's controls can make it hard to move the
player character in very small increments.  The "safe zone"
where you can touch the item but remain outside the pit is
extremely narrow.

One basic method is to walk straight up to the Soul Sphere,
carefully getting very close without touching it.  (Using
the D-pad instead of the joystick may allow you to move in
smaller, more controlled increments.)
At this point the Soul Sphere will appear rather large, and
its lower edge may appear at or slightly beneath the bottom
edge of the first-person view.
In a smooth motion, move slightly forward and quickly back,
so that you just touch the Soul Sphere and step away as the
floor of the chamber drops down.

This may take several attempts to accomplish.  If you find
yourself trapped in the chamber, simply press Start to
pause the game, go to the Options menu, choose Password and
press the A button to restart the level.
If you successfully escape the chamber, take care to avoid
the other 4 crushers that will be coming down behind you in
the main/central room.

Note that this item accounts for 50% of the Items score for
this level.  (A Berserk Pack accounts for the other 50%.)

Click here to see screenshots from an actual game where the
Soul Sphere is taken away by the player.

Good luck!