Almost happened to me.Was not something I thought about before then.Good thing was that it happened about an hour and a half before our date ,so the firemen and cops were already gone.
It was a 4 star non  smoking hotel.Guest  were told that a woman tried to burn a paper in her room  that sets the alarm off .We all had to evacuate to the parking lot.
Although she is a seasoned provider, I  have no doubt the situation would have  freak her out if she had showed up at the said time - unless I could make quick contact . Something to think about if you are staying at a non smoking hotel.

I was with this client in the middle of our 90 min appt outcall.. he freaked out!  

I was with a lady that I had seen a few times. She had just mounted me when the alarm went off. I looked at her and said "What do we do?". Her reply, "Let's keep fucking!". We did and it turned out to be a false alarm. I really miss her.

The first time the gal had just left a few minutes and I was about to get to bed since I had a big licensing exam to take early the next morning.   Fortunately, my floor was told to stay put and await instructions, and I never had to evacuate, but I did lose a few hours of sleep.  (I passed the exam, anyways.)

I just looked at your website. A fireman with an axe couldn’t have gotten me out of that room with you.

As soon as we finished, the room was filled with smoke, the alarms went off and within a minute or two security was knocking on our...Oh, her gift caught on fire but all ended well.

...college dorm...YES!!!

It happened to me, but it turned out to be a false alarm.  This happened at the Monte Carlo in Las Vegas ca. spring 2008.  Construction workers were still in the process of renovating those upper level floors that were damage from the fire that broke out earlier in January of that same year.  

Once, about a year ago, a wonderful client of mine was just putting on his coat to leave when the fire alarm went off. We just sort of looked at each other and laughed. He headed out first and I waited a bit before going outside. Never did find out what set off the alarm but I was able to go back in about a half hour later. Makes for an interesting story!

once in the middle of a 1hr.  thank goodness I didn't have anything after so I made s sure he got his full time.  Another was nearing a close and were just chatting on the bed, decided it was time to go.

you're not alone! When I was in Dubai in a very glam hotel, they forgot (I never will know if with with intentionality or not),
to tell me that thy had planned a fire drill, I was on a 13th floor and when the alarms started to sound hard and people were running down the fire stairs, I remembered that when there is a fire you don't have to take the elevator.
I was on a date with a client and we ran like crazy. When we found out it was a sham it was a relief, but the appointment got so cold that we could not continue and we ended our failed hot encounter.

I was seeing a newbie and right before our session the fire alarm goes off. He arrived ten mins later and saw cops everywhere and panicked... I tried to convince him that it was safe but he was wayyy too freaked out. Stupid fire alarm lol.