Looking for a story

I only remember one scene from the beginning or near the beginning of this story, but it has been annoying me that I can't remember the rest of the story or the title. In the scene, the protagonist is a janitor in a research lab or chem. lab where a female scientist is working. Initially, the scientist is very protective of her work and sees the protagonist as a threat to it. During one night where the protagonist and the scientist are alone in the lab, a small chemical fire or acid spill occurs and is dealt with by the protagonist in such a way that shows that he has some basic understanding of chemistry. This act builds up at least a basic understanding between the protagonist and the scientist.

I'm not too sure what happens after this scene, but I am eager to find out again. Thank you in advance if you reply to this post!