The key passage to look at in order to examine this is the closing soliloquy of the play where the bell tolls signifying one hour until Faustus is taken to hell. Even at this incredibly late period in his life, as he approaches damnation, Faustus is still attempting to procrastinate and to delude himself, asking his soul to 'the this hour be but/A year, a month, a week, a natural day'. He is in the perverse theological position of knowing that, if he offers his repentance sincerely, he is in a position to 'repent and save his soul' but even as he utters this speech, he narrates it in the third person, referring to himself as Faustus as a form of rhetorical distancing of himself from the situation that he has created. One might understand this to be simple delusion or distancing himself from his situation. However, one might also read it as a sign of Faustus's perverse academic interest even at the point of his own damnation, that he still wishes to see what happens, that this is a form of metaphysical experiment for him and he views himself from a distance as he can't really repent because he wishes to see what will happen to his soul.
Faustus does not, indeed, believe the evidence of his own eyes when he sees 'Christ's blood' in 'the firmament', even knowing that 'One drop of blood will save me'. This is, perhaps, a hallucination at the point of death or, perhaps, an allusion to the sacrament of the eucharist and the saving blood of Christ which he cannot freely receive as he cannot sincerely repent before reception. This results in the blood disappearing ('Where is it now?') for it is only an illusion to a man who cannot repent. Thus, the bargain with his soul - that he is able to repent at any moment and thus gain salvation - is one that in his final moments, he realises he cannot fulfil. Indeed, so complete is his realisation of this inability to repent that he asks the 'Mountains and hills' to fall upon him in order that he can be hidden from the 'heavy wrath of heaven'. However, God is powerless to intervene if he cannot exercise his free will to repent his sins. He craves divine influence to assist him and allow 'my soul to mount' and, indeed, wished to bargain once more even with the devil that he might 'Impose some end on my incessant pain' - the contradiction here (i.e. to create an 'end' to the 'incessant') is used to demonstrate his predicament, that he has nothing left to bargain with but his soul. Indeed, he wishes even to become a beast rather than a man at this point, believing, according to the accounts of 'Pythagoras' metempsychosis' that the souls of animals are 'dissolved in elements' unlike his own. However, his problem once more here is that he cannot divorce himself form a questioning intellect that, even at the hour of his doom, cannot realise his predicament and act sincerely but instead has to seek theological loopholes. He cannot become a beast quite simply because he is human, has an intellect which, rather than being pure and simple like that of an animal, is questioning and inquiring. Even at the moment of his being dragged to hell, Faustus still takes no responsibility for his actions or sincerely repents, asking his soul to be 'changed into small water drops' that might 'fall into the ocean' in order to avoid capture and, when this does not work, his final words are the claim that he will, finally, divorce himself from his intellect (I'll burn my books') but, at this point, the bargain that he has made proves too late and, where he might have performed this act and repented sincerely, he has left his negotiations too late and his soul is torn from a body that is 'torn asunder by the hand of death'.
Dr. Faustus is a man who is unsatisfied with life and with all of the professions available to him. It is this dissatisfaction that leads him to delve into the dark art of magic. It is during this time that he makes a pact with Lucifer and sells his soul. Faustus finds himself in turmoil, but the devils have a way of bringing him back to their side each time. It is near the end that Faustus negotiates with his soul. He no longer wants to exist and asks his soul to turn into drops that will go into the ocean and never be found.