The Nuclear Option (Railroad)

 is a quest and Fallout 4 achievements and trophies in Fallout 4.

Quick walkthrough

 * 1) Talk to Desdemona
 * 2) Talk to Z1-14
 * 3) Kill everyone in relay room
 * 4) Talk to Desdemona
 * 5) Use terminal to override Institute lockdown
 * 6) Reach the reactor
 * 7) Plant fusion pulse charges inside reactor
 * 8) Talk to Desdemona
 * 9) Speak to Tinker Tom
 * 10) Step into relay
 * 11) Use the detonator
 * 12) Talk to Desdemona

Bugs
Teleporting into the institute wearing power armour with this quest active makes the player partially hostile to the institute, denying the player access to the elevator and not spawning any institute NPCs except Father. Reloading a save from before entering the institute for the final time and taking off the power armour is recommended, though the quest may be completable with copious abuse of tcl.