"The Bunker" is a side quest available in Dying Light.
Note: It is written that you will get 10000 xp points for completing the mission. However during the course of the mission you can get supplies worth more than 70000 xp points which makes it the best mission for those who want to lvl up. Inside the surprise Safe Zone on the Northern side of Old Town you will find a man named Ihsan who is sort of the Supply Sergeant there. He tells you about a rumor of a secret stash of supplies that is being horded by the former Town Clerk for the Old Town.
Ihsan thinks we might be able to convince the guy to share out some of those supplies - or perhaps that we may prefer to kill him and just take what is needed. Either way he does not care.
When you reach the building the entrance to his offices is along the balcony past the bar - you head in and have a chat with him and he tells you about The Bunker. He then dictates to you the forms you will need to take possession of it. Forms? Really?!
He tells you that what he needs is the Mayor's embossing stamp. Seriously. So you need to head to the Hotel, find the Mayor's room, and thus the stamp.
The Hotel is an Instance Zone - when you reach its roof you go down inside via a hatch - which is the Instance trigger - at which point should we remind you that you are now indoors? That means you can safely use firearms here if needed. Just saying.
You make your way through the first floor taking out the infected, then use the hole in the bathroom wall to drop to the next floor and take out even more infected before finding the right room and the seal in a locked trunk.
With the seal now in hand the next objective is to give the seal to Thabit - the Clerk... Really? The town is wiped out by a virus and he still wants the proper paperwork??
When you turn over the seal you learn that this guy knows what he is doing - turns out the seal is sort of like a money press for him - though what he is going to do with all that power under these circumstances?
But that is not our problem - our problem is to get to the Bunker under the Town Hall!
When you reach Town Hall you need to drop down to ground level then enter the sally port there and use the door to enter another Instance. The Bunker.
The Bunker Edit
First a word of warning - this area is NOT infected free! In fact a trio of Bombers are inside the door on the left so you may just want to pull out the old Shotgun and blow them up BEFORE they get close enough to do you harm!
With them - and any other infected that come in - managed, Before you head down to the next level below following the pointer be sure to loot what there is to loot here as there is a considerable amount.
Sadly when we get to the next level down and pick open the door what we find is that this area is, if anything, worse in terms of infected effects than above! A glow-in-the-dark Toad immediately attacks.
The Bunker door is still locked - and we need the passcard to get in. There is still a chance that the contents are intact it seems. But we need to find the zombie who WAS the big cheese cop and get the passcard from him... Back to the outside it seems!
Is this taking longer than you thought it would? Yeah, me too!
Okay! You know that bruiser type that tosses concrete chunks? Yep! That's Captain Hareem! Now you can deal with him any way you like but I decided that discretion WAS valor, so I sat on the metal ledge above and emptied clips from my Assault Rifle into his head until he died. Yes, I had to deal with some runners, but all in all I think I came out ahead on that deal!
With the big guy dead it was just a matter of clearing out the lesser infected and then looting his body to get the key and, with that done, a quick trip back to the Bunker!
Now were you really surprised that the Bombers had re-spawned? Not me! I anticipated that!
What I was not expected but should have was to find the Clerk waiting at the door with the word that he had taken “ownership” of the contents of the Bunker! Yeah, nothing a shotgun blast to the head does not quickly fix.
Now inside the Bunker we find that the infected situation was pretty bad but that the door to the supply room is locked from the inside. Never fear a quick jump up to the duct here and then through gets us inside where there is a treasure load of supplies including LOTS of Disaster Relief Packages!
Yes - take all you can carry - which come to think of it is all of them! You radio to share the good news and that nicely wraps up the mission!