Yes, there are surprise rules.
Surprise
When characters are surprised, their attackers can automatically take their first action before the "surprised" side can act. The "surprised" side cannot roll defence skills to dodge or parry this first action.
Each opponent will roll Spot or Perception checks against a DC I determine, based in this case on a sneak roll. If they pass, they can take actions normally. Any that fail will be unable to take actions or react for a number of segments based on the degree of failure, somewhere from one to three segments.
During a round, each attack / defence phase is a single segment. As you are firing two pistols, you get two attacks each segment. If you fire a total of six times, that will take three segments.
Everyone does their first segment, rolls attacks and defence. When the last person in the initiative is done their first attack, the second segment starts with new attack and defences rolls. We repeat the process until everyone has executed all their attacks.
So you might get 0-3 segments on each individual on the other side of the hatch.