Actually, if we assume our allies are also scions (Which would make since story wise as out allies are all player characters) that when all hell broke lose before the Nebralius fight that allies came running to our aid. (Small room in a small building means SOMEONE was bound to have heard that explosion)

As for Ravana, he actually tells us that he will wait until we are prepared. So we easily had time to tap the Scion linkshell and go "Guys, I need back up in The Dravanian Forelands asap. Meet at the Gnath Stronghold." and every one port/ride over there in a short amount of time.

Remember also, that story wise teleportation is instantaneous. So porting to Anex Trine's Aetherite + a short ride (And even shorter flight) could have got 7 others there in minutes.