Shortly thereafter, we found out that, when Caroline is scared enough, she urinates continuously...and she can't stop it.
After Max sees this, word of Caroline's accident spreads like wildfire with Max and Sophie (played by Jennifer Coolidge, whom some of you may remember as Stifler's Mom from the "American Pie" movies) both taking shots at Caroline over the incident.
Later, Max and Caroline snuck into a theatre to see a movie and saw their boss Han (played by Matthew Moy) in the same theatre sitting with a guy and a girl...then the three got up and left, to which Max and Caroline, being the curious people they are, chose to follow.
Caroline and Max followed Han into the washroom and then, as they heard him coming, left quickly. Max walked past the approaching usher very fast, leaving Caroline there to deal with the problem herself, with the reason for Max's desertion of Caroline being that, during the robbery at the diner, Caroline tried to use Max as a human shield to protect herself.
The usher asked Caroline for her ticket and she was flustered, but, as luck would have it, Han exited the bathroom and Caroline, thinking quickly, pretended that she was with Han. The usher asked Han for his ticket and Han didn't have it so he began to urinate out of fear, which, naturally, led to pee jokes from Sophie and Max later on.
(there was also a moment during the episode where, when Max and Caroline went into the bathroom to look for Han, Caroline said "he's not on the changing table." [most likely a crack at his height since the actor is only 4 and a half feet tall to Kat Dennings' 5 foot, 4 and a half inches and Beth Behrs 5 foot 5 inches], but I'll admit, with Caroline's previous wetting problem, I would've loved Max to have said, "Speaking of the changing table, how you holdin' up? You need to go up there?")

I gotta admit, after that episode with the drug trial and the "relentless urination", I'm surprised that Max or Caroline didn't suggest diapers. lol Especially with a perfect setup line where Max talks about Caroline treating her as "disposable".
If I was the writer of that episode, I would've had Max say, "Oh, and speaking of disposable, I thought you might need these..." and hand her a pack of Pampers.

This is a .gif I found of Max, Caroline and Han which, I think, best illustrates the height differential.


The above image was taken from the second season premiere where the three of them were watching a woman partake in "Attachment Parenting" by breast-feeding her son who was definitely past the standard age. (I'm no good at guesssing kids' ages, but I'd say he was five or six)