Many survivors in Paris did this instinctively - turning tables over to use as makeshift shelters or hiding behind speakers in the concert hall. But the lack of cover on the main floor of the Bataclan meant not everyone there was able to hide.
An Irish couple survived by playing dead. Another survivor, Theresa Cede, told the BBC: "One guy was badly hurt, and moaning, so we tried to say: 'Shh, be quiet, stay alive and don't move,' because every time there was movement somewhere, there were more gunshots."
"They are looking for movement - it will catch their eye," explains Reed. This is especially true if it's dark. Some people in the Bataclan did run for the exit when the attackers paused to reload. This can be risky, but in some scenarios running away is a good idea. According to eyewitnesses on Friday, several people chose to stay hidden in offices and toilets until help arrived.
Lassana Bathily: "I switched off the fridge... and told customers to stay calm"
In January, 24-year-old Lassana Bathily was hailed a hero after hiding Jewish shoppers in a basement cold store during an attack by an Islamist gunman. He switched off the fridge and the lights and ran to get help. All of those he hid survived.