Yes, she certainly was committing a sin.

With an access of impious boldness, the sinner walked--she ran as far as the corner, and stood still, fearfully expectant.

What form would the punishment take?
She stood breathing painfully for an eternity.

How still everything was--how close and still the air! Would it be a storm?
Would a sudden bolt strike her?
She stood and waited.

She could not bring her hand to her pocket again, but she felt that it bulged monstrously.