You find the parasite nest when travelling b/w abandoned city and city entrance like the milk farm. I think it is a small chance to trigger.
The laboratory events i think occur after you explored the parasite nest.
hm so the parasite nest is a different location from the desert base also what i know about the event of laboratory i see in the wiki and that says i need just the parasite on my body from lost any confront on desert base maybe because i dont unlock the parasite nest they dont trigger yet anyways thanks gunsruth <3
the parasite nest is in the lower levels of the deserted base, but that particular storyline is not finished as of right now; you can get out and have any parasites removed at the science lab, but the arc won't progress yet. as for what is and isn't in the game right now, read indivi's development logs