Saw a medical emergency on my United flight – what’s in those red and black bags?

Was on a flight to Hawai’i when they called for medical professionals. A few passengers jumped up right away, and the FAs pulled out a red medical bag, then later came back for a big black one. The man was moved a few rows up and met by medics after landing.

Kind of intense to see in person. Does anyone know the difference between those two kits?