Sometimes going in alone isn't the best solution, a proper Rogue knows this. You can't always trust your friends to do the job right, or go see a doctor in the middle of no where, so how does one best prepare for this? By building their own friends out of just about anything they can get their hands on.
Strengths
The tower is a great tank even at skill level 1 if used along with Medibots and Repair.
Technological Marvel gives a half skill slot for every engineer skill equipped so efficiently two engineer skills fit in one slot.
Overclock's explosion is also powerful. A good way to further damage enemies that are killing your turrets.
Metalaegis is a great way to deflect physical attacks from you to the machine as long as you stand next to it. And it attacks too!
An ally Engineer is a Mechanation's best friend! And the class alone is great for the race alone.
Drawbacks
Even with Good Materials the machines lose plenty of health for taking actions forcing you to Repair them to keep them up (unless you Overclock them and leave them be).
Terrible autohit gun skills that aren't worth their FP cost at all, mostly because certain gun types don't have high base damage alone to compensate, and the class has no need for a high Fire ATK.
Unlocking
To unlock Engineer, win a battle with a wrench equipped as your main weapon with level 20 Rogue equipped.