What I call a "Zarayna" ending. That's the easy way to end something, I guess. Back in the day, my Imrov friends had a simple way of ending every single improv act. They'd do something and they'd say "Hey, was that just a hydrogen pipeline?" Never mind that a stream of hydrogen gas would mix with the oxygen in the air and form harmless water vapor and that they could have chosen something far more harmful like chlorine. The point was, if the setting was "Helen Keller visiting the Great Wall of China while unknowingly doing the Nazi salute with her hand gestures, provoking a salute back from her Chinese guides" or "Two guys playing pool while one guy plays the white pool ball", they would always find a way to break a pipeline or gas tank that would induce instant death. Call it the easy way out. The teacher said to never use it in competition.
Meanwhile, for exercises, for which this would count given that it is a 15 minute write-off piece, I find this hilarious due to this personal experience. Sometimes I criticize these. Zarayna has now removed me from the list of people to ask for reviews from due to his tendency to end his stuff like this (hence me naming this trope after him with regards to BZP short stories), but other times, like with now, this memory just pops up. I'm glad the theme was Towers instead of Rainbows. The Rainbows ending for Zarayna would have been funny if he had played it for humor, but he had not. You didn't intend this to be funny, either, and so I apologize for my laughter, but the image of my improve group using "Death by Hydrogen" as a convenient way out of any situation just happens to come to my mind.
The sheer number of times I have had to sit down at my computer, straighten my bowtie, and give writers a metaphoric wag of the finger for ending this way escapes me. It's time for a change of pace. To you, I say "Happy birthday!" even though it isn't your birthday (to my knowledge), plan on giving you a high five over Skype the next time you're online (or, if you prefer, an imaginary cookie, another common theme in internet etiquette), and giving a friendly but ever-so-slightly serious reminder that I will hold you accountable if you ever end up writing something that isn't improvised and isn't under pressure that seeks a simple, cheap way out. However, this is not one of those times, so I do not have to be your enemy.
Part of what lets you off the hook, of course, is that you are not Zarayna and you had a good ending line, and at least I got action before someone died instead of a bunch of flashbacks and exposition and long, drawn-out description of mood. Death doesn't need the mood to be set up and flaunted. If a death was dealt to an important and beloved character in a longer work of fiction, and it had been built up over a longer period of time, it would make sense to bulk up the death scene with its due drama in order to make it every bit clear in the readers mind that this was it, but in a short story such as this, you can end the work with the death of the character in the space of one sentence and it wouldn't feel as if there was any pace change.
Now my one (of two) serious critique of your work is the legnth. Everything else is fine. The action is straightforward. The descriptions come of as plain and open, not needing any modifications. I like your style. It doesn't stand out, but it's a great basis to build your writing upon. It actually feels like one of those significantly shorter second drafts that writers talk about. However, given that this is not a second draft and a write-off piece, and that you didn't have time to think about what you were writing as you were writing it, I would have expected you to come up with a little more over the course of this story. It's a little bit shorter than the average write-off piece (well, I would have to confirm that, but I'm not going to check all of them and average them out), and I would just encourage you to keep on practicing and taking part of the write-offs. This is what they are for, to get us to become more natural with our writing process and to get our brains to kick out more quality ideas when demanded with continued practice. For that, I highly recommend that you come back and visit regularly, because if I recall you aren't there every weekend. I'm not either, for that matter, and its something I will have to keep in mind as well, but for the moment the encouragement finds itself directed toward you, as these are my thoughts about your story and how they pertain to your writing as a whole and you as a schrijver (off note: Nederlands is such a cool language and everything sounds better in it). If you don't participate, though, I certainly contend that it's in your best interests to start writing during the weekdays more often, just to get your stuff out there and be established here on BZPower, like I'm trying to hard to.
The other serious critique is that you should certainly add tabs to each of the paragraphs. I had to butcher the last person I reviewed who lacked them. Poor lass. It doesn't take that much effort, and I really encourage writers on this site to use this new feature, because I find it awesome. Also, unless you're like me and occasionally write chapters that are 10k, after which length there comes a point where they can be overused and stop working, I also encourage you to use two of them and create ten spaces, which makes it twice as easy to locate a paragraph and closer to an actual indentation on a Word Document.
In the end, I celebrate your gift to the cause of the CoT Library, your innovative work, your desire to know what you want (I see that you said you wanted something only barely on topic), your resulting honesty, and your acknowledgment on the quality of your work, which is definitely a smaller Write-Off piece, and your gracious afterword, which adds some clarity and openness that I think readers sometimes need in order to connect with the activity of writers. And I especially emphasize the CoT Library cause, wishing to cite a few songs for Les Miserables about revolution but coming back to this simpler acknowledgment of your work: as the Bishop of Digne said, "I commend you for your duties and God's blessing go with you."