Marching to the wrong direction? [Very Minor Spoilers]

Zanso

I was wondering this when I saw this cutscene: when the Flaming Fist starts to march to the north with the player from Ducal Palace and are leaving the city, they are marching towards the gate that leads to Beregost, Candlekeep and etc. Isn't this a wrong direction?

lansounet

I think of that main entrance from BG1 in front of sorcerous shop and elfsong tavern as more of an eastern gate to the bridge across the river. A northern gate exists but I think in BG1 someone tells you it's broken or closed for some reason?

Zanso

@lansounet
The flaming fist soldier just says it is no longer to be used as passage (quite vague). However, in the canon map (http://i2.photobucket.com/albums/y13/Slynt/FRAdventures_BG_zps979fc58e.jpg) the city actually has three exits, which the army could be heading to. But the exit doesn't exist

In Baldur's Gate canon map that came with the game, the northern (and most famous) gate actually says that it is a way to Waterdeep and therefore north (https://images6.alphacoders.com/331/331698.jpg).