Do you mean the flashback when you enter the gardens?
The way to Parliament starts with the right part of the cross-shaped intersection - the door to continue further is at the right side of the next area, next to a save point.
You're heading down to where the second chimera encounter took place (the first time the egg chimera was seen) - after seeing the dialogue in the canals, you can go past the part that was blocked off before. Please don't feel bad about asking questions - it's good to know when the given directions aren't as clear.