My understanding was that one is ok, but swallowing two creates the possibility that they attract and meet each other through different parts of your insides.

But if you happen to swallow one and you are in a hurry: https://www.youtube.com/watch?v=17QKhX-8dm0

Never swallow 2. One is not a problem. Two is a medial emergency.

Wont it shut come out the other end?