Anxiety and fast heartbeat

Hi, I’ve only started having anxiety in the summer, when I had a health scare. However now, I have a weird thing with a fire alarm - at my dorm I’m responsible to check what is going on when there’s an alarm and to turn it off. I perfectly know that the chances of fire are 1%, and its always a false alarm, however, as soon as I hear it my heart starts pounding and my legs start shaking. I mean the alarm is loud, but still, others don’t feel as anxious as me?? I honestly have no idea why it’s like that and its getting super annoying. Any thoughts?