It's not safe here.
How could I have forgotten that the subway runs directly beneath the library's bottommost steam tunnels? When the MBTA was extending the Red Line, they had to dig that deep in order to avoid tunneling into our library's basement levels, which is why the escalator ride into the stations outbound beyond Harvard feel like slow-motion descents into the lower reaches themselves. The ghouls, packed thick into the subway tunnels, must have latched onto a scent above and scrabbled through the substrate - with so many claws and so much force bearing in the direction of what was probably the only living meat within miles it was only a matter of time before they found a way.
We discovered the breach about a half an hour ago, when one of the security guards noticed on the surveillance cameras that something was setting off the motion detectors down below in the Stacks. Sure enough, it was Professor X. A distinguished older gentleman from one of the more prestigious universities in Western Europe, he generally gave himself carte blanche to roam the halls of the library whenever he damned well please, whatever the rules were for anyone else. He was also a notorious technophobe, and probably hadn't even heard the news that the dead had risen and were now walking the Earth. We tried paging him over the intercom system, to no avail - either he didn't hear the message (our system being notoriously flaky and prone to breakdown here and there) or he had heard it and decided that the notice, however dire, certainly didn't apply to him.
Someone was going to have to go down there and get him...
"Professor X?" I called out with ax in hand. The cameras had last picked up the cranky old scholar on C Level, but having roamed that floor of the Stacks from East to West I hadn't turned up any sign of him. As I went to reach towards the door heading to the stairwell, however, I could hear what sounded like a scream coming from one floor up. My heart pounding, I crept towards the source of the noise, which was the break room just outside the access door to the Stacks.
I swiped my card to open the door and turned the corner to see Professor X holding one of the women from the janitorial staff above his head with what could only have been inhuman strength, his normally clenched jaws wide open and dripping with gore. He had already taken a bite out of the poor cleaning lady, whose brain was now exposed in a gooey parfait of cranial matter and blood. As he sensed the arrival of new prey, Professor X let out that awful moaning cry.
Gritting my teeth I swung the ax again, burying the blade into the septuagenarian faculty's shoulder. Professor X howled and raked his claws at me, just narrowing missing my face by centimeters. I pulled out the ax, which came free of the zombie professor's reanimated flesh with a sickening sucking pop, and tried again to cleave through his head.
That's when I heard more moans echoing from the still-open door to the Stacks behind me. They were answering his call! In a panic I dropped the fire ax and bolted out the break room. While these ghouls weren't quite the lumbering slowpokes from many a Creature Double Feature from the UHF Saturday afternoon television my youth, I was still able to escape back upstairs to the Circulation Desk, only to find that the zombies had already made short order of the rest of the assembled survivors - blood and guts spilled over the long wooden desk, and I could only vaguely make out who was who amid the remains. It was probably just as well. Had the ghouls left anything recognizably human, they would almost certainly have been turned into the living dead themselves.
I realized that my only chance lay in getting to the roof and hoping I could keep the zombies at bay as they attempted to mount the fire escape one by one, so without waiting to see who or what would lunge at me next I sprinted up the steps to the second and then third floor of the library, my pace quickened by the sounds of moaning and shuffling below. My ID card could not open the door permitting roof access, so I did what any former MIT student would do in such a situation and slipped the card in between the lock and the doorframe, desperate that an old hacker's trick would work in my hour of need.
CLICK! The door popped open and I was up on the rooftop, at which point my phone began to ring...