How do I stop the assassination?

Hint 1 of 9:

First, do some exploring.

Hint 2 of 9:

Follow that robot!

Hint 3 of 9:

Stay away from people of this time!

Hint 4 of 9:

You should find something suspicious behind a door.

Hint 5 of 9:

Did you watch the video segments in the lab?

Hint 6 of 9:

Then you might have a guess about what to do.

Hint 7 of 9:

You brought the cutters from the Mars trolley, I hope!

Hint 8 of 9:

Cut open the fire extinguisher control box.

Hint 9 of 9:

Turn on the fire extinguisher.