What part of "vacuum" don't you get? Are you in a vacuum on a 99 degree day? Is that 99 degree day made from a 99 degree sun? What does that have to do with human bodies constantly pumping out 99 degree heat? Is there an atmosphere to dissipate the heat on a 99 degree day? Where is that dissipation atmosphere in space? If those bodies keep pumping out 99 degrees into a sealed vacuum bottle that can't release any heat, where will that heat go? If I wrapped you up in a down blanket on a 99 degree day in a sealed room, would your temperature go up? Would you overheat?
Physics is harder for some people than others.
You’re confusing thermal energy and temperature.
Your body doesn’t “pump out 99 degree heat”.
And radiative heat transfer still works just fine in space. You said so yourself. The capsule and everything in it will come to thermal equilibrium, all the while radiating heat out into space.
You’re right, physics is harder for some than for others. Take, for example, the first rule of holes: when you’re in one, stop digging.
YOU need to study thermodynamics a bit more.