i don't know if you are male or female, but for me a shoe that has 1/2 inch square opening of the toe is equivalent for practical purposes of a fully enclosed shoe; meaning if someone steps on my foot, it won't hurt any more or less and my nail won't bleed if something contacts it directly.
more generally - while i agree that being prepared for an accident is prudent, i don't always dress for that simply because it's not practical. high heels would be terrible in an emergency, yet my departure/arrival activities often require certain style of dress and it's a risk i'm willing to take.