I'm trying to do the mission I Put a Spell on You. I staked out the control tower until I saw the mole go inside. Then I ran in and pulled out my shotgun. The mole said "You're getting too close, Seamus!" and pulled out his gun, so I killed him.
The game then tells me to go back to Hsu. When I talk to him about what happens, he tells me to go check on the monorail because he thinks it's been sabotaged. I make a beeline for the monorail, but as soon as I walk through the door to the platform, I hear "The train is departing, please keep bla bla bla" and it immediately rockets off towards the Strip before I can get to it, promptly exploding a couple of hundred yards down the track.
Did I screw up by not listening to the mole talking on the radio, or something? Is the quest not completeable anymore? If so, are there any console commands I can use to fix this?
Best Answer
You killed the mole too fast.
If you enter the watchtower and wait for the mole to finish their check-in on the radio you will hear about their plans to destroy the monorail and gain the opportunity to disarm the monorail's explosives before it can detonate.
If you talk to Col. Hsu before disarming the bomb or kill the mole before learning of the bomb's existence you will be unable to disarm it before the monorail leaves and is destroyed.
You can read more about the layout of the quest from the Fallout Wikia page