Your body can only handle so much pain before it basically shuts off, and then you don't feel much of anything. The real pain comes later, when you're healing.
Not going to test it out though.
Ever had a severe accident, like a motorcycle accident, or been ran over by a car? The pain comes after, not in the moment when the trauma occurs.
And yes, I have been in high pain incidents. I recall the pain happening during and after.
Think what you wish, but sitting there in pain for a few minutes while my life ends (by my own accord) doesn't seem all that difficult comparatively.
I take on very hard tasks daily, and sustain work on them for a lot longer than three minutes.
Don't make me challenge you to a vipassana, friendo.
Why do people put monks on such a pedestal?
These monks practice mindfulness meditation for decades, and as a result, they have such control over their minds that they are literally able to "ignore" the pain of being on fire and sit still through the entire duration.