OOC:
I don't have a ready-made map. Picture a circle. You entered from the bottom of the circle. There are multiple passages off of the circle, including one to the right. You had torches and they had torches. Each side saw the torchlight of the other without seeing the other yet, because you were completely inside the circle, outside their view, and they were inside their passage, outside your view. Ishzu, then left your circle and stepped into the mouth of their passage.
At this point, Ishzu was just outside your sight, though you knew exactly where he was. They could easily see him, but couldn't see you. Ishzu distracted them with conversation and kept them talking, so the idea there was more than just Ishzu didn't occur to them. You all quickly quenched your torches and kept quiet, so you didn't cause suspicion. Note that, except for Ishzu, none of you have actually seen the goblins at all. You have only heard them. (While these goblins don't have a problem with someone using head-speak on them, it never occurs to them to try and use it back. They just talk normally.) Had Ishzu led them back into the circle, you could have jumped them. Alternatively, you could have charged into the corridor spent one move (to get to them) and one attack in a surprise round.
What the goblins originally wanted to do (assuming you weren't there) was to go into the circle, and enter the passage you came out of, go to the pink slime, and then see what they can find in those caverns. When they found Ishzu and heard his story, they were trying to decide whether to not believe Ishzu, then take him with them to find out what happened; or to believe Ishzu, turn around, and take him back to camp for interrogation and further orders. They have apparently decided to believe Ishzu and are turning around to take him back to camp for interrogation.
Also, let me know what you are doing regarding trying to map or keep track of where you are. The goblins know these caverns. You most definitely do not.
As far as goblins in general, they are highly nuanced.
Unlike hobgoblins which have a organized structure with decent cohesion, goblins are very fractured. Hobgoblins in the area are part of a single nation-state. Except for the goblins under those hobgoblins' thumbs, goblins as a whole are not cohesive. Any given goblin group could have a different structure, a different style, a different belief, and a different attitude towards others. And it isn't just the leader. Some groups have a strong leader, but most do not. Individual goblins can have an even wider range of personalities and approaches than even humans. The two main constants are their individuality and impulsiveness. Goblins are chaos. Not always destructive chaos; just unpredictable chaos.
So, if you meet one goblin, do not make any assumptions about what group they are part of until they actually tell you. You can't know unless they are wearing a uniform, and that's not even guaranteed. And extremely rare. But if they tell you, it's probably true. Most likely.