I seem to have missed some of the Master Game clips including this encounter between two great personalities. Raymond Keene was a player with a wonderful understanding of chess whilst Walter Browne was known for his theoretical knowledge. So this game became something of a ‘theoretical battle’, at least in the terms of the 1980s.
Of course offering a draw before you move can be answered by a request to play a move first (the draw offer still stands). Personally I would have responded to Browne’s draw offer like this, even if it is a total draw.