8. Passing Out In Suits
The lengthy spacewalking sequences in Alien were filmed in makeshift suits made of various hockey apparel and diving equipment. Unfortunately, no-one in the props department or any of the producers had thought of fitting air tanks to the suits, resulting in the actors passing out several times as the CO2 levels built up. John Hurt sweated profusely inside his suit, so much so that after a few yards he could no longer see where he was going. The final straw came when Ridleys children were suited up for the wide shots and subsequently passed out after which the producers paid for the actors to be given air.