After the meteor hit the command bunker the phone lost connection and died, later just before the other meteor was to hit the earth and they were about to launch the rockets, the phone connection was miraculously in perfect working order.
Imogene is attempting to start the truck. The driver's side door is open. A few shots later, the door is closed. No sound of a closing door is heard either.
There are many inaccuracies of meteor/asteroid science in the depictions and dialogue.
The line "I need to use the damn phone *now*," was an overdub of a similar line with more colorful language.
At the very end, Stacey Keach and family are having dinner three months later and everything seems to be back to normal, but even at the end of part 1 they said that there was over 100 trillion dollars in damages. This would be more than enough to cause massive disruption to the entire world's economies, starvation and world upheaval.