Early in the game you come across a key stuck on an electrified subway track. Now, this is before you know you're supposed to be a hero -- before you even know a second world exists. So as far as April's concerned, at this point in the game, she's just a regular college student waiting for the subway. It makes no sense for her to drop everything and endanger herself for a piece of garbage on the tracks.
But it's so shiny!
But whatever, that's video game logic for you: Every gamer knows to frantically Klepto-Klutch every item in sight, just in case it might save your life later. So you need the key, sure: But you can't just turn off the power. Clearly, you have no choice but to leave the area entirely and run back to your apartment to fiddle around with a completely unrelated machine.