Got to go!

The two of you travel the next couple of blocks in tense silence before your daughter says, "Dad?"

"Yeah?" You ask.

"I've got to," She makes a face, "Use the bathroom."

"You couldn't have gone before we left?" You ask in disbelief.

"Seriously dad, I've got to go."

Taking a deep calming breath, you glance around the area, seeing a couple of houses, or even an alley that may suit your purposes, "You're sure you cant hold it?

"Dad, I said I was serious, I've got to go." She fidgets a little.

Find a house.
Use the nearby alley.
or
Try to push on.