good explanation for u to safely overtake the slow car in middle lane, using fast lane at what ever ur comfortable speed. that is correct way, overtake from right lane, instead of left one.

however, pls consider if there are signal (beam/flash/yellow signal/hon from far) as the other car from behind is requesting for overteake u.
give way, nothing lose, nothing wrong.....everybody end up continuing their life.

blocking people in fast lane is not a good attitude....
braking as others mention are dangerouse action....