So i was riding down the western ring road doing 95kmh in the middle lane, i indicate for a good 3-4 seconds, check my left mirror and a good head check... nothing. once i finished my headcheck i refocused back on my left mirror and started to change lane... as i started changing lane, i see in my mirror some biatch pulling out behind me and furiously undertook me at 5-10km above the speed limit. lucky i was still paying attention to mirror while changing lane and saw her pop out behind me and forcing me to swerve back right ... phew that could of gone real bad... she even greased me off and then started swerving and undertaking more cars and trucks ... worst! why the **** would you change lane and undertake a vehicle that had already been indicating its intention of a lane change! lesson of the day, check your mirrors (especially behind you if you can), head check and check your mirrors again while changing lane!