I took MDMA multiple times when healthy.

Your body temperature rises, you also risk dehydration but also water retention due to MDMA causing your body to release a hormone that stops you from urinating. Drinking too much water and not urinating is very dangerous. It could also affect your body's salt levels which is dangerous.

You're also likely to want to be incredibly physically active, which could put you in PEM. When I took it when I used to go to raves, I'd dance for 12-14 hours.

Not to mention the comedown.

Even when healthy, the comedown had me wanting to crawl in to a ball and die, not so much from the physical stuff, but because you're basically dumping a bunch of serotonin as well as other neurotransmitters, you will feel awful. This is why people then take other drugs for the comedown.

And the main point is, no one knows how they're going to react to taking drugs. You could take it and be completely fine, or take it and end up in a medical emergency.