The Shadow Girl by Ray Cummings

Alan found himself outside the laboratory. Its door was open, with a yellow glow streaming out. Charlie, clinging to the girl, was with him. The glow fell on them; Alan shoved them aside.

"Which way, Charlie? We've got to get out of here!"

They stood in the darkness a moment against the laboratory wall. The hospital was aroused. A voice had shouted. Others were taking it up. Lights were showing in several of the windows. An uproar -- growing now of its own momentum. Some one lighted a light in the reception room. A shade snapped up.

The courtyard was brightening with yellow glints of light. No one as yet seemed to notice the three figures standing by the wall.

"Which way, Charlie? " Alan was momentarily confused. They would have to pass through the lower part of the building, get into the garden, fight their way through if necessary.

The girl stood docile: Charlie was chattering with fright. A desperation was on Alan; he shoved at Charlie. "Come on!"

But he stopped abruptly. The Indian had come to the laboratory door. He shouted -- vehement, guttural words. An answer came. Dr. Turber! The man appeared in the light of a lower doorway in the main building.

All thought of flight was momentarily stricken from Alan's mind. "Charlie, wait! " They were standing by the upright wheelbarrow. "Look!"

Turber came running. The shaft of light from the doorway picked out his running figure. He was heading for the laboratory door. Not to menace these intruders; knowing only that his secret was discovered. With his hospital in uproar around him, Turber was in flight.

The Indian disappeared back into the room; Turber went at a full run through its doorway. Alan had not thought to try and stop him. Instead, he moved to the door, fascinated.

The room already was empty; Turber had gone through it; was leaping into the vehicle of the inner courtyard. An instant. Then the huge aero -- it was nearly a hundred feet long -- with all its gray solidity, began melting. Dissolving. A wraith of a cabin with wings -- a dissipating phantom --

The inner courtyard was empty!

Charlie's voice: "Look! There it is! There it is!"

From the top of the laboratory building -- perhaps automatically operated by the going of the aero -- the searchlight beam was standing up into the air!

Alan found his wits. "Charlie, for God's sake lead us out of here! You don't want to get caught in this affair."

Figures were now in the courtyard; voices, questioning; at a window of the first story a boy in white nightclothes stood gazing down. The excitement set him screaming -- shrill, piercing, unearthly screams! Voices began shouting at him.

It was a welcome diversion. Alan gripped the girl by the arm. She seemed to understand what was going on. She ran with Alan as they followed Charlie across the courtyard, into a lower doorway. In a corridor a man opposed them. He ducked away from Alan's waving weapon.

Through a dim room, crowded with the silent machinery of a laundry. Through another door. A hall. At the foot of a staircase two nurses in dressing gowns saw the running figures and screamed.

Charlie fumbled at a door; opened it. They were in the side garden.

"Which way? " Alan demanded. "You go back! Nobody recognized you? Pretend you had nothing to do with it."