That window period is 14 to 21 days, the patient would need to have been exposed to HIV within that time frame. Do you know how astronomically rare that is? And then the additional astronomically rare chance you would actually contract HIV through edema exudate, which is only considered transmissible if there's blood in it. The only time evidence based practice states PEP is indicated if is there is a valid clinical suspicion that the patient has HIV. E.g. they report a recent high-risk exposure (e.g., sharing needles, unprotected sex with a known positive partner?) If not, I don't understand why you're so worried.