Each Sector starts with 4 players randomly placed in corner rooms. A large sector is made up of 4 sectors, 16 people.
Can't leave your sector /or enter another( can then use highways still to get around their sector) sector until you are the only one left alive in your sector. Other players who get killed in sectors respawn with other players randomly again( new sector not opened till 16 players are in que so doesn’t give anyone advantage) with now a maybe less dangerous neighbor as all these have been vanquished.
The 'winner' of the sector is now free to invade the other 3 sectors of the big sector, hopefully this will put similar skilled players together after a bit shuffling. This could be done by opening 3 portals in the centre room which leads to other sectors.
4 Big sectors could be combined to then find the winner etc if there's time but not needed as overall winner could be decided by score.
Scoring could be done by holding corner rooms of each sector, maybe having them claimed will allow a ticking score to accumulate. It would be important to then conquer the corner rooms of your sector and then the others as quickly as you could as this will increase your overall score. Corner rooms cannot be occupied, only claimed but maybe you could have some sore of booster building that you fed with a resource to increase base score.
Also best to stay alive in your first sector as you are accumulating score, if you purposefully respawn you could be waiting in a que for a time and not scoring. Others could harass your corner rooms and kill claimer that would stop you accumulating score and would thus need guarding. I would imagine that the rooms bordering the central room with the portal(cant build in portal room) would have defensive measures built ideally to stop others portalling in and rushing to unclaim/claim your corner rooms, lots fights would happen in the centre of the sectors.