Catholic Christians simply accept Christ's explanation of those
still alive at the end of the world.
(In reply, Jesus said to them:) "But of that day and hour
no one knows, neither the angels of heaven, nor the
Son, but the Father alone. For as it was in the days
of Noah, so it will be at the coming of the Son of Man.
In (those) days before the flood, they were eating and
drinking, marrying and giving in marriage, up to the day
that Noah entered the ark. They did not know until the
flood came and carried them all away. So will it be
(also) at the coming of the Son of Man. Two men will
be out in the field; one will
, and one will be
left. Two women will be grinding at the mill; one will
, and one will be left. Therefore, stay awake!
For you do not know on which day your Lord will come."