Taking Toddlers With You To YOUR Dentist Appointment

So, my family situation is complete crap. I babysit for my sister A 3 & 2 year old. And I Have an emergency dentist appointment tomorrow. And she can't take the day off work literally no one can. And I don't have a car. AND the dentist office is pretty small and they have a double stroller. And I'm just gonna take both of them I guess. But is that okay? Like this stroller is big. And I don't want to leave them in the waiting room since it's so small and I'm afraid something will happen to them. Can I take them and have the receptionist keep an eye on them or something? There's literally no other option.