Agree to go with her

Melissa stands up from the table.

"We're headed to the restroom, be back soon." she tells the others.

You follow her towards the restroom. You stand outside the stall and listen to her let loose a flood in the toilet. After she finishes, a couple of minutes pass before she finally exits the stall.

"What took so long?" you ask.

Melissa grins sheepishly, "I had to do a little emergency cleanup. Guess I should have gone a little sooner. Come on, let's get back to the table and see if we still have seats."