With evil scientist, if somebody other than you tries to disarm the trap, there's a 20-100% chance (scaled linearly based on traps skill) that he will take 10-50 electric damage, regardless of whether the disarm attempt is successful or not.
The 10-50 damage might be improved if it's too low.
Too tired to explain how traps skill works right now, but in broad terms, it makes it faster (cost less AP) to arm and disarm traps, it improves the distance at which you spot them, it gives you a higher chance to successfully disarm the trap, for traps with duration (ward traps), the duration is longer with higher traps skill and finally it also improves the damage dealt with traps. I may have forgotten something. The exact amount of influence and the exact formulas naturally depend on the traps themselves.