S. R. Faruqi:

It's a very interesting and multivalent verse. First of all, look at the self-confidence, that in the whole field of the assembly there will be only one person-- that is, myself. It's as if the rest of the people will be of a rank more than human, or less than human. But why did Mir endow himself alone with the rank of humanness? Perhaps because he alone is a sinner, or because he alone has seen all the heights and depths of human life, or because he alone wanted to become an angel, not a devil.

But if 'on my head' is taken to refer to the people who live in the common human world, then the meaning emerges that the Lord, the angels, the devils, all those are excused; no one will say anything to them about what they did and why. The court of Judgment Day will be a problem for the poor humans. Whatever others did, or didn't do, or allowed to happen, there will be no conversation about this. It won't even occur to anyone that, as Mir has said [in {706,4}], 'We humans are weak, how could we stand firm?'. It won't even be asked, if humans are guilty of sins of commission and omission, how much responsibility for these the devil had-- and how much the Lord himself had, who made humans weak and oppressed and ignorant. All the force will be expended on poor humans.

Perhaps under the influence of a vision of somewhat this kind, Iqbal said:

roz-e ;hisaab jab miraa pesh ho daftar-e ((amal
aap bhii sharmsaar ho mujh ko bhii sharmsaar kar

[on the day of reckoning, when the account-book of my deeds would be presented,
you yourself be ashamed, make me too ashamed!]

In Mir's verse there's a strange qalandar-like arrogance and an exaltation of humanity [insaan bartarii]. Iqbal's verse is very fresh and informal, but Mir had passed before him and smoothed out the path.

Here guft-guu has been used with a number of meanings: 1) disputation, investigation; 2) conversation; 3) question and answer. Not all these meanings are in the dictionaries, but they're in the usage of poets. Consider these examples. From the first divan [{548,3}]:

guft-guu re;xte me;N ham se nah kar
yih hamaarii zabaan hai pyaare

[don't converse with us in Rekhtah
this is our language, dear]

Dagh:

log samjhaane lage yih din nahii;N takraar kaa
guft-guu un se mirii roz-e shumaar aane ko thii

[people began to explain that this was not the day to insist,
my conversation with her, on the day of reckoning, was yet to come]

Jalil Manikpuri:

javaab te;G se dete jo maa;Ngtaa bosah
ba;Re maze kii mirii un kii guft-guu hotii

[she would have given an answer with a sword, if I had asked for a kiss
my and her conversation would have been very pleasurable]

With regard to ma;hshar , his use of qiyaamat kaa hangaamah is good too. There is iham upon iham, and idiom upon idiom.

FWP:

SETS == WORDPLAY
MOTIFS == DOOMSDAY
NAMES
TERMS

Truly the wordplay is spectacular. Just look at guft-guu and ma;hshar and hangaamah and qiyaamat (see the definitions above). The elements of meetings, gatherings, discussions, tumult, and Doomsday are widely distributed among the four. We feel their similarities; but in order to make the grammar work we must also notice their differences.

SRF takes 'on my head' to be about an assumption of (moral?) responsibility, like taking up a burden, and that certainly seems a powerful sense. But for something to be 'on my head' can also just show annoyance, as when something cascades down onto someone's head: everyone is pestering him, the whole uproar is vexing, etc. (compare the burden 'on my head' in {107,6}).

Compare Ghalib's meditation on words, crowds, and Doomsday:

G{119,6}.