Well done, no you probably can't strike sparks by breaking a window. Possibly if striking with something metal and the carry through causes it to strike a shard of glass, but no probably not.

As to the rest, I've already stated that the water is above ground level doors, is quick moving and full of debris. Debris may be anything you might find in a city. Since the city is based on Houston during Allison, you can assume buildings are close together. Downtown type area general mix of highrise type buildings. Probably too far from the freeway to get to an overpass. No low buildings with accessible roofs. Let your imagination run wild, though, and insert images of down town in which ever large city you've been to.

The purpose is to think about the consequences of a general disaster (flooding) in an urban area and the situations that might arise there in, not to answer specific questions about a specific disaster in a specific city. Take the basic blue print and run with it.