When we first got into inguanas my youngest was not quite a toddler... we had many stuffed animals in the house.Some with big googly eyes, which we soon found out one of our iguanas, Cricket, was terrified of. In hindsight , testing the thought was cruel , but we would occasionally show her on of said toys to see if her response was the same, and it was- she would literally flip the frik out.
Dif igs fear different things, I had another that was terrified of white plastic grocery bags- and he was the biggest meanest ig we ever had..
we had another that were threatened by people in sunglasses or baseball hats.
another the fears the vets white coat- it is actually listed in his chart so the vet always comes in without his lab coat on.
Your roomie or even you could have done something without even realizing it and eventually you may figure out what it is but for now, patience and willingness will serve you well.
I do want to mention double checking basking and cool zones in the enclosure- an ig that is 2 hot, even if they are not panting, will act out in some way, usually more aggressive.