 Why are the police willing to risk the life of Gerri to kill Lane?
Raging , Trooper Lane hovered three thousand feet above Tammany Square. The cool cybrain surgically implanted in him was working on the problem. The humming paragrav-paks embedded beneath his shoulder blades held him motionless above Newyork's three administrative towers. They don't teach them about their own city, that they'll be fighting for. Two black paragrav-boats whirred along the translucent underside of Newyork's anti-missile force-shield, the Shell. Cybrain had taken charge of his motor nerves. Lane dropped lightly to the floor, inside the room, in battle-crouch. "Lashing police with his vibray," said the announcer, "Lane broke through the cordon surrounding Manhattan Armory. Two policemen were killed, four others seriously injured. Tammany Hall has warned that this man is extremely dangerous. Citizens are cautioned to keep clear of him. Lane is an insane killer. A built-in electronic brain controls his reflexes—" "At ease with that jazz," said Lane, and a sheathed finger snapped out. The two police boats were hovering above the towers. Lane's mailed hand snapped open a pouch at his belt. The force-bomb "exploded"—swelled or inflated, really, but with the speed of a blast. It shaded the view from his window and re-entered the tower wall just below. "Trooper Lane, of the Newyork Special Troops, is all." If you've never heard of diplomatic immunity, you'll suffer for your ignorance."
 Lane is too dangerous to be left alive. They can't risk him escaping just so they can rescue Gerri.
 Lane is too dangerous to be left alive. They can't risk him escaping just so they can rescue Gerri.  They think Lane may be infected with a biological weapon.  The police don't care if they kill Martians.  They don't believe that Gerri is in the room with Lane.