 Why do Harvey and Joe change thier plan when confronting Johnson about the water?
"Now do you see, my hot-tempered colleague?" said Harvey as he and Joe picked up buckets that hung on the tank. Harvey studied it worriedly, put his own hand somewhere on it, swallowed as it closed, then breathed again when his fingers were released in five units instead of a single compressed one. "You'll find everything you want in the back room," Johnson said frantically, "sulfopyridine, mustard plasters, rubs, inhalers, suction cups—" "Relics of the past," Harvey stated. Instead of replying, Harvey hurried outside to the ungainly second-hand rocket ship in the center of the shabby spaceport.
 Joseph's son is large and intimidating, and they want to avoid a fight.
 Joe suddenly feels unwell, and Harvey needs to help him.  They want to buy Genius, and don't want there to be bad blood.  Joseph's son is large and intimidating, and they want to avoid a fight.  They don't think they could take Joseph in a fight.