Jia Tengying observed carefully; the stone table was close to the eastern wall, which was the wall where the main entrance was located, and Yu Huaijin stood between the stone table and the eastern wall, facing the stone table with a ruler in her left hand and her right hand empty.
He was now on the right side of the stone table. If he walked directly over, it would be inconvenient to pass things across the table, and if he walked behind her along the eastern wall, it would be awkward for her to receive with her left hand holding the ruler. She would need to bend her arm in an unnatural way.
The only choice then was to adjust his position, starting from the left side of the stone table and choosing to pass behind her to hand the cucumber directly to her free right hand. This way, it would be easy for her to receive and convenient for him to pass it.