The amount of times people go afk when they are supposed to be paying attention and are the person guarding the flag or node – only to come back dead, or have a team-mate screaming at them ” Halp!” as they are being cut to pieces by < insert random class> and they sit there mounted oblivious.
With team mates wanting to know why they didn’t call for help – ” I was peeing” is a common response.
Biological urges – you can’t really argue with that.
But it’s a 20 odd min bg at the max really – some of these things can be taken care off before you enter the BG.
“Have you pee’d before entering the BG?” its like a teacher, or a mother asking kids ” did you go” before you leave.
In my house when whenever we went on a car trip or going somewhere – making sure we pee’d before leaving was a given, especially on a holiday trip where toilet stops and breaks were planned by distance.
Besides the buff/cookies/mage food call in the preparatory time when you enter a BG should we also be asking.
” Now have you all gone Wee wee?”
It is a tactic of stealthies to approach a node being guarded by one person, and not even attempt to sap/stun or anything to them. Like sly predators they sneak up to you to see if your still alive, and if you’re not paying attention they will cap it under your nose and if it’s a druid bounce away chuckling gleefully, or a rogue, just ‘Pops’ vanishing
Not all of these stealth caps are because of people on Bio breaks. Plain boredom, inattention or just standing out of line of sight will do it too.
But needing to pee!
Why didn’t you go before !
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Pugnacious Priest's Warcraft Blog 
I can stave off my own biological urges until after a match, but my dog is another story. He’ll start whining, which means I have about five minutes to get him outside before he pees on my bed.
It only takes me about 45 seconds to let him out, so I try to do it when I die. Then let him back in a few minutes later whilst dead again.