Summary (a quick, 2-3 sentence summary): Right so, after 2 hours or perhaps 2 hours and 30 mins .If the aliens this was ticked (As in it was 2 hours in or 2 hours and a half into a round) the plasma doors north would either open or be deleted allowing aliens and other players alike to walk in.To stop it from being camped by the marines I've been thinking that It could be randomized somewhere in the caves each round.
Through the plasma doors at the very far northern caves could a be a ladder, when down the ladder you would enter a ( which would save time editing the map and instead would allow there to be a separate z-level room which might be easier for devs) small research building which could fit in it some very neat looking looking research "things" and of course the occasional dead body or two, somewhere in that room would be a dead empress body which presumably was being tested on by some secret researchers working for WY. Perhaps on a table in that room there could be a small vial (Or just the actual sprite of jelly) which contained empress jelly. Once the current queen has swallowed the vial/jelly sprite there could either be brief evolve timer which would be around a 10 minute wait or that it would instantly allow the queen to evolve into the empress.
For people who don't know these are the doors up in the northern caves I am referring to:

Benefits (How this will benefit the server and game as a whole): Would punish marines for falling back and would make them think twice before leaving. To make it so it wouldn't just be meta knowledge a chat line like " You feel the ground shake, it feels as if the tectonic plates are moving and something is opening, you hear an almighty howl in the distance. What does this mean for you are you're squad?" also the marines would get a random autmated transmission from WY stating that their secret lab has opened up and inside there was a experimental test design for a railgun. ( Well along the lines of that)
Would also give aliens another reason to protect the queen abit more.
Details (Description of how you think this would work, the benefits, etc): i think I covered most of this in the summary.Just to make it partially balanced as well inside the research room there could be a WY railgun which would me unmeltable and unmoveable while in that room ( So basically the railgun would be in a display case which was unmeltable, but marines can pick it up and use it. The railgun (Would also have limited ammo as it's a prototype) would add in a risk and reward to getting it and also kind of balance out the aliens getting an empress, this would also hopefully encourage marines to stay on the planet.
Implementation (Optional, if you have an idea how to implement it): Coding and possibly some new sprites as well. ( Quite alot of work )#
Sub note: I already know this has been posted around 2 times before by other players, however I believe this has most if not all of the other suggestions problems fixed.