The line "Parting with his poison-flash of diabolic tail in the dark room he risked rain again" can be interpreted in a number of ways. One interpretation is that the scorpion is so desperate to escape the dark room that he is willing to risk getting wet again, even though he knows that it will make him more vulnerable to attack. Another interpretation is that the scorpion is so confident in his ability to escape that he is willing to risk getting wet again, even though he knows that it will make him more vulnerable to attack.
The line "Parting with his poison-flash of diabolic tail in the dark room he risked rain again" is a powerful and evocative image that captures the scorpion's desperation and determination to escape. The line also conveys a sense of danger and suspense, as the reader is left wondering whether or not the scorpion will be successful in his escape.