[6yyyyyy]

Why can't they both take the respective pill? That way nobody has to trust anyone else.

[pessimizer]

That doesn't follow. You have to trust people to have taken the pill.

If the pill worked when you took it 5 minutes in advance of the act, you could both watch each other take it and find something else to do for five minutes. That's not the case.

[CodeShmode]

You just need to know that you took your own pill