I like this idea, I was also thinking maybe something along the lines of capture the flag. Every 3 hours or so the entire layer becomes accessible to all players, all the players who enter the layer during this period get put into random team/squad groups with players joining a certain squad depending on their level (eg if the only people who enter the layer in the time period are a lvl 3.5k and 7 level 500 players than one group will have all 7 lvl 500 players and the lvl 3.5k will be on a team on his own)

Once the time from the opening of the layer has passed (10min time or something) and all the groups have been sorted, the players in one team (this applys to all teams) get together and are given a random team name, flag and playernames (playernames should be linked somehow to team names to make it easy to identify a person to their team) The group then gets a 3 minute stratigy/planning time to talk together (this all happens in 1 galaxy per team/squad) Once the stratigy time is up the players are then able to warp out of their galaxy into a straight chain of galaxies.

This is where the PvP commenses and again I'll say that this is based on capture the flag. Players try to from their gal (We'll call it Gal 1 for now) to the oppositions galaxy (Named Gal 6) These gals are connected together in 1 straight line (gal1-gal2-gal3...) At each end is a scoopable item (named -teamnames flag-) Scooping it will make a symbol appear on your ship so the other players can identify that you have the flag. Once you have the flag you have to get back to your own team's galaxy and dock at a base to finish the flag run. This ends the game and all players are booted out of the layer.

~What happens in between~ While players are trying to get the other teams flag there is endless pvp going on. If you are killed then you automatically respawn back at your teams galaxy (auto respawn means faster gameplay and more action for all involved) And your free to continue trying to get the other team/squads flag. Once a player has obtained the flag and attempts to get back to their own gal, they can be killed. If this happens they'll respawn back at their own gal, but the flag is dropped where they died. The flag can then be scooped by either friendly team mates that will continue to try and return the flag to the base. Or the enemy who will scoop the flag which will automatically return the flag to the teams gal (This is so a player doesnt carry the flag around with them)

~Why would someone do this game?~ So I've explained how the game works, now I answer why someone would want to play this game in the first place. The reason is simple and one that I'm sure would make many players happy. The answer is credits! Basically the team that wins the capture the flag game will be given credits. These credits will be relitive to the players level and how active they were in the game. (Again I'm not good at formulas but something with the players level, how many times they killed another player, the amount of times they held the flag, number of times they returned a flag to their own base and if they were the one to bring the flag home (possibly not this suggestion as it would cause inteam conflict for who holds the flag) Basically the payout should be enough to attract both low leveled and high leveled players.
Once the players have either won or lost/booted out of the game they recieve the credits and like in whoever's suggestion it was, the players appear in all random places, this means that if the player wants to, they can boast all they want that they were the winning player, or they can just go quietly on their way with their winnings.

Optional Stuff: Possibly holding the flag causes a reduction in speed, damage and/or shields.
At any time a player can dock at their teams station and choose to leave the game. This means they'll get a small credit payout but nothing in comparison to staying to the end of the game.
For the player who returns the flag they are given a star or something on their name. Cause everyone loves stars
A consolation prize for the losing team as well in the form of credits.
Another possibility is that you could have multiple teams playing all at once, with a middle galaxy connecting all the teams galaxys by about 3 warps. This would mean a team that has their flag captured would be booted out of the game but the team who captured the flag would continue on to be able to capture more flags and therefore get more credits.

I think this is just about the longest comment I've ever written... fewf.