Oh man... funny topic. Funny now, but not when you're in a bind and needin' to go! My worst one... I was headed to the S.O. to answer a pretty urgent nature call when a domestic came out. I was passing the entrance to the trailer park where the call was so I thought I'd whip in and keep things cool long enough for the zone guy to get there, then turn it over to him and head for the restroom. Well I pull up and long story short end up hand to hand with the drunk perp as soon as I get out of the car. Try fighting while you're pokin' daylight with a load!
Anyway, the zone guy pulls up and says, "What can I do to help?" I threw the guy in his back seat and told him to get the info for the report and explained that I had to go. I don't know if the adrenaline dump magnified the urge, or if the call was just tired of being on hold, but I literally had to run code to the South precinct and just BARELY made it. The S.O. was maybe three miles further from the call than the pct. and I honestly do not think I would have made it there.
Another similar story that was much funnier when it happened because it wasn't me...
I was in the squad room doing paper work when the Sgt came in and sat down. He had this sick look on his face and didn't say anything. He sat there for a minute, stood up and grabbed his stomache and said, "Oh Shit." We had just been issued new leather gear and the belt fastener on the duty belt was still tight and hard to fasten and unfasten. He started trying to unbuckle his belt and couldn't get it. He yells, "Oh G..D...!" and shoved his gun belt down over his hips to the floor still fastened, tells me to watch his gun, and waddled to the head. I was still laughign when he came out. He didn't find it as funny as I did until later.