The Photo (100 Word Story Challenge)

I saw a challenge online to write a story with only 100 words. Here it is!

The Man looked up suddenly, glancing around the room. The rumbling was growing louder, spacing out into individual low booms, like footsteps.
‘It’s him,’ he thought. ‘Oh God, what have I done?’ He quickly rifled through the photos before him, looking for it, any sign of it.
‘I must find it before…’
The steps grew louder, accompanied by gunshots. A loud roar echoed throughout the facility. He was undeterred, however; He must find the photo. It has to be in here somewhere…
He found it, four pixels of his face in the distance.
The door burst open. He is here.