Semi-OT: How do I remove bad associations from bedtime

Over the past few weeks, bedtime and drifting off to sleep have ended up being a nasty time filled with trying to relax, but failing due to that process getting linked to the building's fire alarm going off and waking me. It was initially just a little bit of an annoyance, but after last weekend's hallway full of smoke, it has kicked up the annoyance level. It is now at the point where if even a car horn honks (the alarm is similar in tone) when I'm sleeping or going to sleep, I wake up on the verge of panic and it takes a few minutes to calm down enough to make another attempt at sleep.

Any suggestions on how to get to sleep easier for the next few days?

Toronto is such a beautiful place.
I'm sure your anxiety will pass.
Listen to some soothing music; have some herbal tea.
Enjoy your lovely city.
It's been 42 years since I've been there.

That is the kind of thing unrelated to sleep apnea. Maybe check with your doctor about seeing someone regarding anxiety?

Absolutely right. Semi-OT covers it, IMHO.
If you can get help with the anxiety, great.
My regular doc RX'd me with generic alprazolam for temporary anxiety--
You could get something that might help.

Start with making some changes to your bedroom. Re-arrange things, hang a new decoration. Anything to break up the mood of the room and make things pleasant. Even a deep cleaning can help change its associations.
Use some music or a white sound machine, a fountain or something to change / break up sound.
Find an object which is calming to you. When you wake up suddenly grab it and make it the reminder that you are safe.
Scents also work that way.

I agree with all that's already been suggested. Having been through a similar experience several years ago, your post reminded me of how difficult the times after the fire were in regards to sleep. Since I was unable to live in my place after the fire, I didn't have to face sleeping in the same place where the ordeal was experienced. Can't imagine how that would have felt. All I can offer is that success breeds confidence, and every night you get through without a crisis should bring you to a more comfortable state of mind. Remind yourself that the alarms will wake you if need be, and have a plan and a backup plan in place so that sleep doesn't feel like such a dangerous place to be. For instance, for a while I kept a folded wet washcloth nearby in case I woke up to smoke again. Just the little things in preparedness can help one relax a little. Best wishes as you work through this.