Got "caught" copy-pasting on an online assessment but wasn't trying to cheat?

I applied for a trading firm the other day and got sent an online assessment to complete. Brainteasers, probability, the standard stuff. There was one question that I thought was kind of interesting but I was running out of time on the test, it seemed rather hard, and so I decided I just wouldn't do it. But I still wanted to know the answer, so I tried to copy paste it into a word doc to do it later.

Lo and behold, the test prompted me with an "We've notified the company that you tried to copy paste, which isn't allowed" and I legit panicked. I clicked the wrong button, and exited out of the test entirely, with several questions left entirely undone. I feel like an absolute idiot. I wasn't even trying to cheat, I was doing the test in good spirit, and then I had the absolute worst reaction to being "caught", which I'm sure is going to make me look even more guilty. Do you guys think I should email HR to explain the situation or just give up?

I guess I'm blacklisted from that company now. :(