She absolutely does.
If a condom slips off, she (or anyone) should consider that for that incident the condom was NOT effective birth control (especially if no one took it out right away), and should seek out emergency contraception (and later STD and STI testing, esp. in an instance like this).
It's too late for EC, but it's been enough time for her to take a pregnancy test. I suggest she does that now.
I'd also suggest in the future that she not drink to excess for exactly this reason and numerous others.
Editor and Founder, Scarleteen
My epitaph should read: "She worked herself into this ground."
-- Kay Bailey Hutchinson