The pit was empty, no water, but full of snakes and scorpions. The pit is the mind, water – Torah, snakes and scorpions – bad thoughts.
Joseph's brothers threw him into an empty pit, an environment without Torah and full of spiritual dangers, negative influences from all sides.
A crisis in life is a trial. There, lying in the pit, Joseph could have brewed thoughts of hatred towards his brothers, who, out of jealousy and hatred of him, stripped him of his clothes and threw him into the pit. Succumbing to such negative thoughts is tantamount to inviting into one's psyche snakes and scorpions.
Besides symbolizing Torah, water appears in the Bible idiomatically as a mirror that reflects the face of one that looks into it, and reflects emotional vibrations of the heart of one person to another. Water reflects emotion: If you love me I love you back, and if you hate me I hate you back.
This gives a new, positive interpretation to the Torah's description of the pit as being empty of water. Joseph was able to overcome the nature of water to reflect emotion, the temptation to brew thoughts of hatred towards his brothers. He thereby saved himself from the imminent threat of the snakes and scorpions.
He was able to keep his head in the right place, to concentrate on the Divine Providence at work, suddenly finding himself alone in a pit, without water and full of lurking dangers. He turned to God and asked Him to save him, acknowledging that maybe he also was to blame in causing his brothers to hate him. He promised God, "If You get me out of here, I'll try to improve and get my act together."