This has to be one of the most interesting solo quests in the Burning Crusade.
When you start the quest, Doctor Vomisa gives you the Scrap Reaver Controller. When used, you'll gain the Scrap Reaver X6000 under your control, just like a hunter or warlock pet (not direct control, like Mind Control). The Scrap Reaver has three abilities at your disposal. All three abilities are on a linked 10 second cooldown. One ability is a two second stun, which isn't nearly as useful as the other 2 abilities in almost all situations. The second ability is called "Smash" (http://www.wowhead.com/?spell=34618). It deals a large amount of instant damage, and causes a very large amount of threat, as the tooltip describes. You should use this as soon as the fight starts to be sure you or any allies you have helping you do not get aggro from Negatron. He hits extremely hard and should only be tanked by the Scrap Reaver. The Reaver's last ability is a self-heal, named "Repair" (http://www.wowhead.com/?spell=34619). It heals 10,000 damage over 10 seconds (1000 per second), regardless of the odd/buggy tooltip. This ability should be used early, and not as a last resort after your Reaver is low on health. Be aware that Negatron has a 75% healing effect reduction ability called "Demolish." Try to time your repairs when your Reaver is not afflicted by Demolish.
This quest will take a few tries, so don't get frustrated if you aren't able to complete it at first. It's a decent challenge, but just be patient and get a feel for when to use your Reaver's abilities. Be sure not to walk too far away from Vomisa's console, or you'll lose control of the Scrap Reaver and Negatron will make a beeline to you, and he is much faster than players on foot.