Surprise
When surprise is possible, roll 1d6 for each side which might be surprised; most normal characters are surprised on a roll of 1–2. Surprised characters are unable to act for one round. Characters or creatures which are well hidden and prepared to perform an ambush act from surprise on a roll of 1–4 on 1d6. Some characters or creatures are described as being less likely to be surprised; reduce the range by 1 for such creatures.
The foes of surprised characters can take a free action before Initiative is rolled.
Clunking brutes
Explorers traveling in a large party underground with light sources and metal armor clomping on stone floors are not going to surprise anything or anyone.