Worried; Help please!

<p>So, I received my fall semester grades yesterday in the mail, and got all A's. Unfortunately, I received a U under "work habits" in Physics because I've been tardy 9 times. BUT the only reason I've been tardy is because that teacher does not let anyone use the restroom during class, so I go during passing period, and there often tends to be long lines. The main point of this post, I guess, is that I'm worried my acceptance into USC will get taken back because of this U, when they see it on my mid-year transcripts. Is this something I should be worried about?</p>

<p>You could always write to admissions and explain your situation; it just might sound a bit silly (albeit funny).</p>