Is it complete shut down of perception and detachment of physical world?

As we know people who stay in coma or unconsciousness "experience" timeless,space-less, absolute emptiness and total detachment from physical world. Even though I used the word "experience" will not suitable to describe the situation in coma or unconsciousness state. It is a condition with no happiness or sorrow, no pain,no darkness or light,no noise or sound etc....and finally we can say "unconditional state of mind." and closer to description of "Nirvana" 1. what happen when person die during the coma or unconsciousness state? 2. Is this similar to Nirvana? (as total detachment of world.)