Rogan reaches into the compartment and begins pulling on one of the gears, and the party watches as the portcullis raises itself up into the ceiling.
He then pulls out some spikes and pitons from his pack and sets about trying to jam the chain and gears that drop below the compartment leading to the pressure plate. After a few seconds, suddenly the group hears a *snap* of metal and Rogan jerks his right hand out of the compartment with a curse... the hand now sliced open and dripping with blood. Before he can do anything about it though, the sounds of gears immediately begin to grind, and the Guardian yelps in surprise and shoots his hand back into the wall. Rogan desperately starts working harder as he sees the links of chain in the wall begin to move, but thankfully is able to get a spike through a link and jammed up against one of the gears, stopping the chain's upwards progress. (Disable Device check DC 25: [9] + 14 = 23 + 4AP = 27 *success* / Rogan spends one action point)
The rogue breathes a sigh of relief, and brings his right hand to his mouth to clean off the blood. He nods to the group, and Donovan tentatively puts the breastplate he grabbed onto the pressure plate to check... and sure enough, nothing happens. The group is free to continue forward.
In answer to Donovan's question... Rogan sees nothing within the compartment that would indicate it controls the door at the far end of the corridor.