"That noise you heard? Nothing. Just a few shots," Mr Rashid reassured his caller. "And they were quite distant - 200 yards away, at least." Needless to say, the visitor failed to keep his appointment in Orangi, and Mr Rashid, who has become acclimatised to bullets flying outside his doorstep, seemed genuinely surprised by that.
Earlier the same day, Mr Rashid had watched from his window as a convoy of 25 jeeps and armoured personnel carriers loaded with Rangers in full combat gear rumbled by. The Rangers, Pakistan's elite paramilitary force, were dispatched to reinforce a contingent that had already taken position along the ridgetop above Orangi. ''The Rangers know that if they come to Orangi in a smaller convoy, they won't come back alive," Mr Rashid said glumly.
Karachi's death toll is rising alarmingly: 800 were killed last year, while 900 have died in the past six months, with 130 murdered this week alone. Like every person in Karachi, Mr Rashid is distressed by the city's plunge towards self-destruction. But unlike most, Mr Rashid has tried to do something about it. As chairman of a social welfare programme known as the Orangi Pilot Project, he has spent years trying to remove the sting from the ethnic rivalries that exist among the Pathans, Punjabis, Baluchis and Mohajirs - the descendants of Indian Muslims who came to Pakistan after the 1947 Partition - who are all crammed into the Orangi slum.
Mr Rashid and his mentor, Aktar Hamid Khan, an old Sufi scholar who writes children's stories in his spare time, convinced many Orangi slum-dwellers that the "art of survival" depended on all ethnic communities pitching in together.
They dug sewers, hired teachers and nurses, planted trees and helped each other through a co-operative bank to build their tin shacks into real houses. Even though the project gave loans without collateral, its low record of defaults would be the envy of any British bank.
"We divide the defaulters into three categories: dishonest, incompetent and unfortunate," he explained. "These days, they are mostly the unfortunate ones. How can people work with so many bullets?" The "art of survival" means buying a gun. Ethnic communities that once planted neem trees together are digging war trenches and barricades against each other and the Rangers' armoured cars.
Rooftop snipers pick off mothers and small children; the pistol is being replaced by a rocket-propelled grenade; and even the Rangers are afraid to enter many Karachi neighbourhoods. Yesterday, the Mohajirs forced the city to shut down. Those shopkeepers who don't strike are visited by youths with automatic rifles and cellular telephones beeping in their pockets - calls from gang leaders saying which shop to hit next.
So what is happening to Karachi? The angriest people are the Mohajirs, who make up the majority of the city's 12 million inhabitants. Until the mid-Eighties, they were jostled out of jobs and power by the native Sindhis and the other Pakistani ethnic communities living in Karachi.
Then, after the 1985 riots, in which police failed to protect more than 120 Mohajirs from being killed by Pathans, the Mohajirs began arming themselves. Under Altaf Hussain, leader of the Mohajir Quami Movement, they became feared by some Pakistani politicians and courted by others. The former prime minister Nawaz Sharif was one who feared them; in 1992 he sent the army into Karachi to clean out MQM armed gangs.
Mr Hussain fled to exile in London, and the MQM seemed defeated. To split the MQM, the Pakistani army gave support to a breakaway Mohajir faction, the MQM (Haqiqi), said by many Karachi businessmen to comprise blackmailers and thieves. Benazir Bhutto, the Prime Minister, has compounded the mistakes of her rival, Mr Sharif. Instead of letting Mr Hussain return and holding municipal elections, which the MQM would win, she is using security forces, unsuccessfully, to try crushing the Mohajirs' party.
Inevitably, other ethnic communities are being swept up in the battle.
Tired of having their lorries burned by Mohajir gunmen, the Pathans and Baluchis are kidnapping and torturing to death Mohajirs who stray into their neighbourhoods.
As for Mr Khan - the storyteller and Islamic scholar who once brought peace to Orangi - he is in a US hospital with heart trouble. "I'm glad he's in America," Mr Rashid said. "I wouldn't want him to see what's happening to Karachi.''