You see a sign written in front of you! Try out the Increased Musculature BOOTH! It reads...'Try out this magical booth and witness the incredible buffing up effects of our nano viruses! Top technology makes you look like twice the man!'
Crumbs!
You decide to take a look inside the gray building. Inside is an empty room... empty but for the presence of a conical shaped booth in the centre. It has a door, and it's open.