Hide in a trunk, as bad an idea as it sounds, turns out to be a good idea. The troupe passes you by without anyone being discovered. The three of you carefully enter the main room. There is a Sarcophagus open that the Doctor recognizes as Osirian technology. A spacetime portal, in fact the same one that brought Marcus to England. The Doctor disrupts the tunnel using the TARDIS key. The spatial-temporal back-blast knocks him out.
You are now stuck with an unconscious Doctor. This will not do.