Things to do in this case :
1) buy a camera
2) ask someone with a steady hand to film part 3
3) cut the pieces away.
Now two things could happen :
a) nothing happens and your swivelseat problem is solved.
b) the thingie happened to be some kind of mechanism that explodes, sprays oil gasoline or liquid fluid , ignites the airbags, makes your car fall apart completely.
In case A, all is fine.
If case B occurs, well... then at least you might still be able to win that flat screen tv by sending in the tape to "funniest home videos".
So what I'm really trying to say in a sort of sarcastic kind of way is... take a picture cause nobody here has even the slightest clue of what you are talking about.
I think (but really...do take that picture...) that its the sensor that locks the swiveling when you're driving.
What year is your Van from? CAuse they always told me that you cant put captain chairs in the old types because they are too small.