Trump speaking over everyone was to drown out the voice in Biden"s ear.
"It also adds to the difficulty for whoever was feeding info to Biden. Those people needed to be able to hear what Trump said in order to respond, but they also had to feed Biden responses, and the faster pace and chaos would make it harder. Trying to tell someone else what to say and make sure they say it right, while simlutaneously listening to another person's wordy interruptions, is a lot more challenging.
Good thing they knew what was going to be asked... made it easier to just have a script you could pull from like the call center operators do—those little "chunks" of speech that are prewritten for responses to common questions."
