If fire alarm rings and this happens what is a probability of retake?

I took this physics exam in university (midterm) and during the testing period (near the last half an hour) the fire alarm rings. The invigilator did not say anything so all the students kept writing the test and ignored the alarm. I was confused and the fire alarm did not help me panicking abit and ended up wasting 30 minutes. I think the chances of me getting a low mark is high. Can I petition this with the teacher for a rewrite or not possible?