Another nonsense theory for you all:
Android Bishop perhaps got infected with a version of the Plagarius Praepotens when impaled by the Alien Queen or before, puking the diluted contents all over Ellen Ripley as they attempted to assist him, getting undressed and likely also washed before sleeping she throws her clothes over a ceiling support to dry, in contact with human organic material it gradually constructs a clutch of new Eggs, most ended up on the ground, one congealed to the nearest surface that being the ceiling.