The Lucky-Pozzo episode in both the acts of Waiting for Godot sets forth the difference and repetition structure that holds sway over the entire play.
1. According to Bert O. States, it represents the tragic plot of this 'tragi-comdey' with the comedy being the two-tramps plot.
2. It is a kind of a happening; a chance-encounter with the Other.
3. It introduces the theme of power into the play in a fore-frontal way. It is a kind of a master slave dialectic where it is the constantly shifty nature of power that is at the centre. The episode is in this sense, the political core of the play. It is a subversive portrayal of the dialectic.
4. In the second act, their 'fall' is a self-reflexive symbolic mimicry of the Christian myth of the Fall of man. Beckett's production-notebooks suggest that he wanted them to fall in a way so as to create the shape of a cross--the act of crucifixion.
5. Pozzo's blindness makes him dependent on Lucky, who has already dislocated Pozzo's trope of mastery over him with his 'quaquaqua' speech and his own dumbness is an attestation of the fact that he has already dared to say the unsayable, or as Beckett would put it--"eff the ineffable".
6. Pozzo's fixation with movement and journey ('On' is his recurrent maxim) in which Lucky too is forced into, creates a contrastive frame to the time of waiting where Didi and Gogo are located.