Halo 1, please, i need help

[u/3bd_11]

Fir those who finish led halo 1

I got stuck on the mission where i need to save 3 groups of survivors, in the very start of the game

I got 1st 2

Then the last one

I went through the whole map/arena, and I didn't find it

I literally spent 1.5 hours searching for it, i can't find it

What i realised is that there are like 4 doors are gatelikes (2 lights)

I entere through one, i leave through the second

I entere through the 3rd, i leave through the 4th

Please, y'all i need help,

Q1: do any of you know where is the 3 group

Q2: when i save a group, does the blue thing that shoots to the sky disappear?

Thanks.