Yeah, being honest i think that the GM has been rather merciful (Please don't kill me for saying that), the problems that have arose have been mainly from players causing them. Not going to point fingers but mistakes were made, but have made for a pretty good story. ;)
I think that opening up the city would be grand idea, if we do manage to resolve this current situation, then scavenging within the city might become necessary later down the road when supplies become scarce inside the apartment block. 
Also, i have some great ideas for our survival later along that road. (I've seen a lot of zombies films)