Interior
Upon entering the Stronghold's interior, you'll find yourself in a dimly lit, claustrophobic environment. The Lycans here are more aggressive and often appear in groups, so be prepared for sustained combat. Your primary objective in this initial interior section is to clear the path to the main chamber and locate the crank needed to open the next gate.
Immediately after entering, check the small alcove to your left for some Handgun Ammo. Proceed cautiously down the corridor. You'll encounter a group of three Lycans; two will charge directly, while a third might attempt to flank you from a side passage. Use your shotgun for crowd control if they get too close, or pick them off with headshots using your handgun if you maintain distance. After dispatching them, search the area thoroughly. There's often a small pouch of Lei hidden behind some crates near the far end of this first corridor. The crank you need is located on a workbench in a small, dead-end room off to the right, just before the main chamber. Be wary, as another Lycan often ambushes you as you pick it up.