In Coleridge's "The Rime of the Ancient Mariner," why does the crew’s joy shift to horror?

In Coleridge's "The Rime of the Ancient Mariner," the
mariner has killed the albatross, the bird the sailors believed had brought them fair
winds by which to sail.

When the breezes cease to blow, the
crew is marooned at sea, with no way to move. They are also unable to take on supplies,
and water becomes very scarce.

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Water, water,
everywhere,

And all the boards did
shrink;

Water, water,
everywhere,

Nor any drop to
drink.

The days pass on in
the same way. Until...

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Through utter drought all dumb we
stood!

I bit my arm, I sucked the
blood,

And cried, A sail! A
sail!

The response of the
crew is one of relief and joy believing another ship has come to save
them:

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Gramercy! they for joy did
grin,

And all at once their breath drew
in,

As they were drinking
all.

The crew's joy turns to
terror as they ship draws closer, when they see it is a ghost ship. Death and the
Nightmare Life-in-Death are "casting" dice, gambling. When the game is over, the crew
draws back in horror:

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One after one, by the star-dogged
Moon,

Too quick for groan or
sigh,

Each turned his face with a ghastly
pang,

And cursed me with his
eye...

Somehow the meaning of
what they have seen between the two entities has been clear enough to the mariner's
shipmates: they curse him, and then each man falls down "in a lifeless
lump."

Whereas the men were joyful believing they were
saved, they are delivered into the hands of Death, all but the
mariner.