Yes, I think it is about Karachi. I believe the name Karachi is also mentioned, but the audio is not that good. But it is said that Brahama and Saraswati emerge from there, they adopt these names there. ShivBaba also comes there. There is something spoken about entrance and people going into trance just by seeing. This tallies with the Murli point that when he comes, he starts narrating Gyan and we can know he has come if he narrates Gyan and Murlis have started from Karachi.
I am not so certain, but i think i can hear the names Bombay and Calcutta also being mentioned. We know that visions have started in Bombay. Then he went to Varanasi. There were other references that was pointing that in Varanasi, Brahma Baba realized some power was working in him, has entered etc, so I was thinking that in the mind of Brahma Baba, entrance has happened in Varanasi, hence Magadh desh. I don't know if this is what is meant here.
Finally we have references for entrance in Bengal, Karachi and Varanasi.But whats is being mentioned about Karachi goes along with the advanced knowledge that entrance has happened there only in Brahma Baba. This is also proved by the fact that it is said that Brahma and Saraswati emerge from there, adopt their names there. When the Supreme Soul enters he names the one Brahma. It also rises questions about the time before that in the Yagya.
If Magad desh would refer to the whole of India, it would not make sense to use it in one sentence. It is said I come in Bharat in Magad dehsh, it means i come in Bharat, in Bharat. You suggest that Magadh desh rather means a condition, like degraded land, or a point in time, like Lanka is the same Dwarika in different points of time, but we already have Dwarika for heaven and Lanka for hell, i don't know why would some other name used for he same thing - hell. I would rather see Magad desh as symbol of the Confluence Age. Baba comes in Magad desh, he comes in the Confluence Age.
The meaning of crocodile can refer to the character of the soul, like fearsome and capable of eating everything suddenly and the whole of it. People from UP are considered like fearsome etc. Ganga is connected with crocodile anyway. The name Farukhabad is also interpreted like the one who will eat later.
Even if the reference is about Karachi,I believe this is in limited sense and there is also unlimited sense.