"You've worked with a lot of junior officers off the perimeter lines, haven't you?"

A red streak of light crossed a perimeter line and closed with the station's lower hemisphere.

"Not projected to intersect perimeter line at this time."

If the physical made it a duty day off the perimeter line, that was an added bonus.

Somehow, he expected coldness in battle and on the perimeter line, but not in a medical center.

They found two more perimeter lines, one waist-high and another at chest level.

Be certain to walk directly in toward it from the perimeter line.

As we crossed the perimeter line, they were still pounding at it, swearing.

The Anarchists' first perimeter line was only twenty meters ahead of them.

The division met little opposition and secured the planned perimeter line around the airfield area that afternoon.