Join Date: Oct 2006
Location: London, UK
Programs: BA Gold, VS Silver, SQ Silver, IHG Plat Amb, Hilton Gold, Marriott Plat, Accor Silver, Radisson Prem
Posts: 16,871
You must absolutely NOT run in the main or side CTA tunnels. That would be very unsafe. Pedestrians are not allowed, and the likelihood is that you would be stopped from doing so.
You could run up and down the T5A-B-C pedestrian walkway. Just watch out for buggies.