This app was mentioned in
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for next time, try the gohere app on your cell. It will tell you where the closest washroom is.
gohere on googleplay
gohere on itunes
On this topic, if you are also interested to include the factor of whether the venue permits the public to use their washrooms, there is a useful listing in this app for people with medical emergencies seeking bathrooms here.
I haven't used this is some time but it worked great when we needed it.
The GoHere™ Washroom Locator App for iPhone, android and even Blackberry
Is it the Crohn's and Colitis Canada's GoHere: Washroom Locator app?
It's available on android as well.