“This Is What Happens to Your Brain as You Are About to Die”, animated, from the Infographics Channel, Nov. 29, 2020.
The main point here seems to be that if your body dies before your brain does, your brain has a chance to shut down slowly. The brain, even without oxygen, can shoot itself up with serotonins in the last few moments to make them pleasurable. People talk about a “life review”. Time may slow down and it may seem eternal.
On the other hand, if the brain is destroyed by traumatic injury (like a bullet or explosion), or even by a burst aneurysm, no such opportunity exists. That is something that a terrorist could try to take advantage of. It could also mean that violent suicide by weapon means there is no such afterlife preview.
The short mentions the two films "Flatliners" (1990, which I saw, and 2017) (tidbit review of 1990, Joel Schumacher, Columbia Pictures).
Look at my review of Eben Alexander’s “Proof of Heaven”, Books blog, March 30, 2013.
Hashem al-Gailhi reports "Your Brain Still Works After Death" (2018) and a few memory cells may work at the cellular level for up to two days, possibly growing cancer cells. Yet bodies are often cremated within that time.
Wikipedia embed of comparative anatomy of human and shark brains, click for attribution.