I don’t think it means what everyone says. Remember the timeline of this day:
-Joe lands in NV and goes to some restaurant to shake hands
-Complains about feeling like shit, tested for COVID
-Cancels speaking rally there and heads back to AF1
Its possible this “medical emergency” was just a precautionary thing either towards how he was feeling before the test or even after. Once they realized it was just a cold they said Ah fuck it emergency cancelled.
The other hole in this is that Biden was pictured getting on and off AF1 not even hours after the “medical emergency”. So somehow this emergency was so bad they were going to rush him to a local ER, said fuck it, then he was fine enough to get on a plane to Delaware