With the imprint secured, we just need to get the master key out of Bladder's hands and into ours. Hopefully he washes them.

See the signpost for the Keymaster's directions.

Bladder is distracted by the monitors, but definitely won't let you just take the key.

We could try subliminal monitor messaging to make him want to leave the room.

If the monitors were lit in a way that resembled letters, and those letters reminded Bladder of the bathroom, he would have a hard time staying focused.

Honestly, this puzzle has an incredibly obscure solution.

You need to switch the lights on / off in various rooms to make the monitors spell out 'WC'.

Don't feel bad for not understanding - it's a strange puzzle.

Click the question marks below to reveal the rooms you need to light up / leave in the dark. To create the "W": ? To create the "C": ? To just see what the monitors should look like, see this quickhint. ?

Bladder was distracted by the TV, not the monitors! We need to stop the TV from working.

You won't need to interfere with the TV directly - just stop it from getting signal.

TVs get their signal from an antenna - you passed one a long time ago, but should still be able to access it.

Return to the roof by going to Doctor Marcel's office, climbing through the air vent, and following it to the left.

'Use' the antenna to thoroughly ruin Bladder's day.

Not so fast - we still need to grab the key from whatever bathroom he ran to!

The closest one to the control room, of course - the one on the third floor.

Click the quickhint if you need directions. ?

He won't let you just take it, of course - time to use our clay!

If you didn't already make your clay more malleable, use it on the sink in this bathroom to do so.

That's another step ticked off the list! Now all that's left is getting the gold!