Comment by chasil

I don't think that was a factor at all.

They likely would have returned to their enclosures because of the cold.

  "Many other experts have pointed out that since
  chimpanzees do not like the cold, they would have been
  likely to return to the ape house."

The risk to human life was the paramount concern.

  'Beldt told me he had relived those days perhaps 1,000
  times, wondering if they could have done anything
  different. Every time, he comes to the same conclusion:
  no. Chimpanzees can turn, and the line between play and
  violence is thin. Beldt remembers a time when he sat
  talking to Linda through the bars of the enclosure, and
  Manda snuck up and jabbed him with a stick she had
  sharpened with her teeth, just centimetres from his left
  eye.

  '“People without any experience of chimpanzees say: if I
  had done it, I would have got some bananas, and they would 
  have gone back,” Beldt said. “And maybe, but maybe not.
  Maybe you would have ended up in a body bag, or in 1,000
  body bags, because chimps like to tear things from limb to 
  limb.”'