In the Loop : Karen's teeth

I know this is a really odd question, but there's something that's always bothered me about this movie.

.why on earth does Karen start gushing blood from her gums???? Was she so stressed that something ruptured??

That's what I thought at first, but gums don't bleed that much. I figured with a chipped veneer, she accidentally sliced open her lip and didn't even notice.

I think it may have been to show she cared so much about her job that she didnt care if her teeth were aching.

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See, you? Get me a *beep* Curly Wurly, right?