Changed

There was a guy about 20 years old in the laboratory. Plump, unshaven, not very neat, wearing glasses, he was hovering over papers, quickly writing something down, crossing it out... And it was unclear why this was: either the calculations did not add up, or the nerves could not stand it.

You've looked into the lab. You should have given you the folder. The guy was scared when he heard the creak of the door, which made Nikolai jerk and the handle fell to the floor.