How does the Doom Guy trigger the Soul Cube?

Question

From the Doom wiki, when we first pick up the Soul Cube, it tells us:

Destroying evil gives us life, and makes us stronger. Unleash us when you hear our call. We will pass the life force of those we slay to you. We foresee a great battle, but the outcome is not clear. We are the only way to destroy Hell's mightiest warrior.

And every time it is charged we hear:

Use us!

What is the in-universe explanation for how the Soul Cube is actually triggered? How does the Doom Guy communicate to the Soul Cube he wants it to activate?

Answer 1

In-universe:

The Cube does not have a physical firing mechanism, but it follows the wishes of its owner precisely.

Out-universe:

The Soul Cube attacks intelligently; it always attacks the enemy with the largest amount of hit points within range, and homes in on the target.

The above and Further information can be found on the doom wiki.

This site on Doom 3 weapons says:

When it is ready (by telling you Use us!) you throw it at an enemy like an Archvile or Hellknight.

If this is the in-universe explanation, wouldn't it be too easy to trigger? Perhaps it requires the throwing action combined with the "wishes of it's owner".