Looks like you don't actually have to fight the Mechanist in order to end the quest: if you find all the voiced holotapes (Chief Scientist's, Facility Manager's, and Lead Engineer's), you can go back to the elevator and use them to reach the Mechanist directly, avoiding the battle.

https://www.youtube.com/watch?v=QYhrm2Z8tbM

You sir may have just allowed me to actually complete this quest. The battle for me has been bugged so much for me that I can't complete it. Thank you for this information.

Oh...... I found them all... but I'd rather take out a s***load of bots. Thanks though!

You can also hack the terminal iirc

Just checked it. You can heck the terminal, but you still need to insert the holotapes in order to trigger the Manual Override and activate the elevator.

The battle is worth so long some fancy legendary spawns. You may also get some nice xp as well. I let her live so I get some quests to do. Looking forward to hunt down some bots.

Cheers,

-Klevs