What you do is, you put the camera on a tripod on the angle you want on the person, then you have them do the entire scene but only their "side" (someone else reads the other person's lines for the person to react to, preferably the other actor). Then you do vice versa. Even though it's doing the scene twice, it saves time I think.
EDIT: On the subject of noise continuity, it's fixed in post since I'm pretty sure most films do coverage like this, considering in most coverage if you were shooting with two cameras you'd see the other camera.
EDIT: On the subject of noise continuity, it's fixed in post since I'm pretty sure most films do coverage like this, considering in most coverage if you were shooting with two cameras you'd see the other camera.