there?"

McAllen shook his head. "Not unless that someone happened to break in
within the next half-minute." He considered. "Let's put it this way.
The Tube's permanently centered on its two exit points, but the effect
ordinarily is dissipated over half a mile of the neighborhood at the
other end. For practical purposes there is no useful effect. When I'm
going to go through, I bring the exit end down to a focus point ...
does that make sense? Very well. It remains focused for around sixty
or ninety seconds, depending on how I set it; then it expands again."
He nodded at the locked door. "In the cabin, that's disappeared by
now. Walk through the space where it's been, and you'll notice nothing
unusual. Clear?"

Barney hesitated. "And if that door were still open here, and somebody
attempted to step through after the exit end had expanded--"

"Well," McAllen said, moving over to a wall buzzer and pressing it,
"that's what I meant when I said it could be embarrassing. He'd get
expanded too--disastrously. Could you use a drink, Mr. Chard? I know I
want one."

* * * * *

The drinks, served by Fredericks, were based on a rather rough grade
of bourbon, but Barney welcomed them. There was an almost sick
fascination in what was a certainty now: he was going to get the Tube.
That tremendous device was his for the taking. He was well inside
McAllen's guard; only carelessness could arouse the old man's
suspicions again, and Barney was not going to be careless. No need to
hurry anything. He would play the reserved role he had selected for
himself, leave developments up to the fact that McAllen had carried
the burden of his secret for twelve years, with no more satisfactory
confidant than Fredericks to trust with it. Having told Barney so
much, McAllen wanted to tell more. He would have needed very little
encouragement to go on talking about it now.

Barney offered no encouragement. Instead, he gave McAllen a cautiously
worded reminder that it was not inconceivable they had an audience
here, at which McAllen reluctantly subsided. There was, however, one
fairly important question Barney still wanted answered today. The
nature of the answer would tell him the manner in which McAllen should
now be handled.

He waited until he was on his feet and ready to leave before
presenting it. McAllen's plump cheeks were flushed from the two
highballs he had put away; in somewhat awkward phrases he had been