Really what is the point of the bunker?
 

How will putting a house mate with 3 ex housemates for 4 days advance the show? It's not like the ex housemates can win or will enter the main house. So I can't see what can be gained from it.

An attempt to improve the viewing figures.

That's pretty much it. Otherwise it doesn't add anything more. Saves Marc for the producers and keeps drama going for a week or two.

The ex-housemates are entering the main house...

The fake evicted housemate (Marc) will watch them on the TV, and go back in the house with all this stuff to complain about.. He'll probably be given some sort of power for no reason too, he'll get immunity. Probably get to be the only one to nominate too.

A few extra ratings, not that they'll last though. The show will probably fall back into it's slump a couple of days later, if not sooner.

Really? That might be more interesting if it happens

Just said on BBBOTS that the evicted housemate will be in the bunker for 48hours.

there is the sunday night reboot show with Rylan ....

They're in the bunker for the weekend and then they enter the house until Friday.

I am surprising myself here saying this, I will wait and see and how it goes.
Normally I would be saying it will be a waste of time but am prepared to give it the benefit of the doubt until it happens.