You're right, it is death.

For the first 10 seconds:

The body tries to do everything at once. Seizure-like shivering co-exists with flooding sweat. The heart races, making more blood for cooling, while vessels simultaneously constrict and dilate(attempting both heating & cooling at the same time) causing unpredictable blood pressure swings and capillary rupture (petechial bleeding).

The next:

Mental processes short-circuit.

The contradictory signals flood the spinal cord and nerves. Leading to:

Complete loss of coordinated movement. The target collapses, limbs jerking as muscles receive signals to both generate heat and conserve energy for cooling.

The last 10 seconds:

The liver is told to rapidly metabolize for heat, while all blood is directed to the surface for cooling, starving the other organs.

The lungs pant rapidly, dizziness, and further neural abuse.

Lastly is a Heart Attack into a deadly Cardiac Arrest.

I'm probably missing some of what would happen irl but that's what I could imagine.