After Lily loses the medical party while traveling through the Jefferies tubes, she meets Picard, and uses his phaser against him. He then takes Lily to a room, with a hatch that open into space, with a force field, and a control station. What is the room used for? I see no conceptual double sliding doors, so that rules out a entry area.
It's called an umbilical docking port.
The scene you describe appears in the transcript as follows:
[Enterprise-E umbilical docking port]
PICARD: There's a... There's a new faction that wants to prevent your launch tomorrow morning. But we're here to help you. This may be difficult for you to accept, but you are not in Montana anymore. You are on a ship, ...a spaceship, orbiting the Earth at an altitude of...
LILY: If you want to help me, get me out of here.
PICARD: All right. ...You want a way out. Here it is.
(Picard opens a panel in the hull revealing a view of Earth)
The (non-canonical) Chakoteya transcript is backed up by this novelisation:
"We're not the ones who attacked you-"
Picard finally spotted the umbilical docking port, which looked like a small room that sloped outward at a forty-five-degree angle. He stopped, wondering if it wouldn't be better to give her her wish. If they couldn't get the Borg under control, all of them might have to abandon ship.
"There's a new faction that wants to prevent your launch tomorrow," he lied. "But we're here to help you."
The Memory Alpha page on docking ports is here.
For more discussion of this particular scene and room, see this review (start at 5:00):