When putting the car seat in the backseat should I put the car seat in the middle or behind the…

When putting the car seat in the backseat should I put the car seat in the middle or behind the driver? It's my boyfriends car and he's the only one who drives so I'd be getting him out. Since its a two door it's a little hard and I figure behind the driver would be the best since I have to slide into the backseat