Your food will cook for somewhere between 3 and 7 minutes. It will be unevenly heated. You will enjoy the aroma of 20 years of popcorn being blown out of the side.
Enjoy your half frozen leftovers, and kneel before the unkillable microwave.
60 seconds can have a totally different meaning from 1 minute. First, there are leap seconds, which cause a minute to have 61 (or more rarely, 59) seconds. Second, 1 minute conveys a different amount of accuracy than 60 seconds does. Just like you donโt measure house sizes in micrometers and the width of a hair in meters.
I'm pretty sure every microwave just splits the input in to the last to digits as a number of seconds and the digits before that as minutes. Then runs for 60 * minutes + seconds. So 0:99 is equivalent to 1:39 and 1:80 is equivalent to 2:20. I mean it is a little weird that the seconds can be >59 and extra weird that you can do 6:66 but it isn't exactly wizardry.