This actually happened to me, although I didn't realise it until we landed.

I must have eaten something bad in penang and about 4 hours out of LAX I started feeling really bad and shortly after I threw up 5+ times. (I can no longer eat the steak option in F after seeing it come back up) Then my hands and feet started to tingle which had me a bit worried. The FA's took my temperature (normal). They did call the medical service and they said they could give me some medicine but apparently it wasn't in the med kit.

I had a good feeling it was food poisoning and that I'd be fine in the end so I kind of told them not to make a big deal out of it, but we had a super fast approach to LAX and there were paramedics waiting at the gate. Apparently any time they call the medical service the paramedics must respond. They said that the tingling was due to breathing too much (to try and make me feel less nauseous) because there is less oxygen in the pressurised air.

They asked if I wanted to go to a medical place somewhere but I declined as LAX was my final destination. A customs officer walked with us and someone wheeled me out to immigration/baggage claim/ and the curb. I threw up once more on the way to immigration and then slowly recovered over the next few days.

CX handled it very well and I never heard anything more about it from anyone (the paramedics was free)