Did the host have to open 998 doors, or could he have chosen to just let you open your selected door? If he's "out to get you" then you get very little informat

Did the host have to open 998 doors, or could he have chosen to just let you open your selected door? If he's "out to get you" then you get very little information here, because he could have just let you open your door. The only reason he'd open the other doors is to try to get you to switch, which means that it's pretty close to 50-50.