Telyportas

The Shokk Attack Gun is one of the many Ork inventions which usefully combines force field and teleporter technology. [...] Other races also use similar technology to a certain extent, but their fragile nervous systems and feeble bodies are unable to withstand the stresses generated by these powerful machines. Even with heavy shielding and complex suppressing systems, a human or Eldar can only withstand low levels of exposure. However Orks are remarkably resilient creatures who feel very little pain and whose powers of recuperation are quite phenomenal. They can walk safely in and out of teleporter beams which would tear the nervous system of a human into shreds.

'Ere We Go, page 104