Actual HR question.

I was told I will be contacted by HR as I and one other were witnesses to an incident.

Here’s how I would identify the incident: an incredibly petty 30 second argument where the one party upped it to HR immediately on their cell phone because, again, petty.

Given the pettiness of this, my relationship with these two people (amicable), my distrust of our HR, and my trying to fly under the radar, I would like to decline to cooperate. Unfortunately it happens in my cubicle about 3' away from me so I can’t quite claim I didn’t hear/notice anything...

Should I expect retaliation (IRONIC) for not cooperating with HR? I really want nothing more to do with any of this...