I lived in Manhattan although I never had a vehicle. Living on an island definitely creates movement issues.

Here's another option to consider--making friends with someone within Manhattan as a bugout destination. Many situations will be more localized and will not necessarily affect both your apartment and the other bugout location. The power outages I went through didn't affect the whole borough. Subways were flooded in some places but not others. 9/11 happened way downtown while I lived and worked far uptown.

For a rapidly unfolding situation, it would probably be far more feasible to reach another part of Manhattan than getting off the island. I'd rather walk 80 blocks uptown to a friend's place than hoof it across a bridge on foot and then hope to find a way on the other side to continue on to my final bugout destination.

The space constraints certainly does put limits on how long your can bug-in at any typical Manhattan apartment, though, although NYC probably has the most thought-through contigency plans for restoring supplies and services after some incident.