(This is a serious article by a serious researcher. There exists good work on Frontiers in….)

The 5-HT2A receptor is profoundly immunomodulatory. (Acid is arguably a more potent immunomodulator – an antiinflammatory one – than it is psychoactive.) Local inflammation is a thing in injury, "global" inflammation as well – there is strong interplay between cytokines and metabolic/anabolic/catabolic process; Interleukin-6 stimulates osteoclasts which actively break down joint tissue – and neuroinflammation also affects physiology. Muscle tone, blood flow, pulmonary function, and so on.

Ego death happens to be a phenomenon or qualia when you boop that receptor hard. I'm not sure ego death necessary for anything. It might be. Ego death is very intimately related to the individual neuronal state and memory, and inflammation is quite enmeshed with that. (Cf. cortisol.)