"a tiny furtive wedge of darkness beckoned him, a snicket, a hacket, an alley carved into the thickness of the building. it was so narrow that at any moment, it seemed the overtopping walls would come together and squeeze it out of existence…. walking as softly as an indian, jason passed through it, slid by a file of dustbins, and found the foot of the fire escape." jason's actions as he enters the building at night in "sonata for harp and bicycle" show us what?