Yes 100% correct you will end up with Zero plus your have to pay for your own airfare back home .
The reasons why you want to get off are still vague ? Forget the contract most are not worth the paper there printed on .
It would have been much better before you requested off to contact someone on the beach and they contacted the company telling them there was a problem at home and you had to get off ASAP .
But I do know of one guy who locked himself in his cabin and when he got off they charged him for full board and lodging plus the cost of the chopper in the end in his 2 weeks offshore trip he made nothing .
So if I was you I would just accept the job is crap and wait till your relief comes if you cannot you will end up with Zero to show after the trip .
Raptor