I lean toward the connecting point of a PICC line.
However there is the possibility that it is a pressure switch for either the communications device he was obviously concealing, or for a small pump, which was pumping meds through a PICC line, concealed elsewhere, dispensing as needed.
A pressure switch located there could be easily depressed by rotating the wrist down toward the edge of the podium while his hands are upon the sides. It appears to be held in place by his watch band.
Isn’t this the location of the USSS mics?
If it is a switch, then I’d guess it’s most likely for coms.
I don’t understand why people like you have to make this into a huge conspiracy. It was probably nothing or a pen. There’s no way he’d have a 2-piece mic these days, and there’s no way that’s an IV.
This isn’t a good thing to go desperate for, it’s not even needed.