Better just to act. And it was time.

The clock gave her exactly one hour, she knew, to destroy the central building sector, the heart of the giant UN Research Foundation, and also wreck the rocket due to blast for Mars. She had heard Daddy Mike say what time the rocket would blast if he got the G-Agent loaded on schedule, and she knew he had done that.

There was little if any caution exercised at the Foundation. It had been well established by years of precedent that humans just didn't sabotage an effort directed at aliens. Especially Martians who, time and time again, had almost brought destruction to earth in innumerable unexpected ways. Added to that was the fact that no Martian could get across the void to take care of it directly, any more than an Earthman could to Mars for a similar purpose.

Mary had the advantage of this freedom. But the immediacy with which she could be identified by all the personnel about the Foundation might be a handicap as well as a possible advantage. She would have to exercise extreme caution herself.

The directives had stopped. She was on her own as long as she didn't resist the preceding orders. From this point on it was strictly Mary's responsibility.

She checked the electrodoor. No one was approaching Daddy Mike's office. She wasn't sure whether or not he would return to his office before going to Lake House. She wondered what he would do, how sad he would be, to find her gone.

From behind the rearmost, long unused files in the filing cabinet, she took the capsule of G-Agent. There was enough of the nerve gas in the ten ounce container to destroy everyone in the building, within half an hour after it was thrown into the ventilator shaft.

She went to the wall, pressed the button, and the opening was revealed by a sliding panel. Without hesitation, she tossed in the capsule of G-Agent. Dimly, she remembered how she had collected it, painfully over a period of months, drop by drop and stored it in the special non-corrosive alloy of the container. She had access to all of Daddy's laboratory equipment.

The container would explode in half an hour. Thirty minutes to get outside the buildings and over to the pits and the lethal rocket.

She felt nothing but a kind of depersonalized tension of responsibility as she removed her hat and took the small deadly neutron beam gun from the tiny sling she had fixed inside. She put the hat back on and tied the ribbon under her chin. The hat had caused much amused reaction from those friends of Daddy Mike who had become accustomed to her being constantly with the old man.