I remember in the first test, where the dorm room's flooded, they all go to the toilet and put the hose in it to breathe. They explained too quickly, could someone explain how it works?

  • I don't get how the toilet wont get filled up by the water rushing in. Doesn't this go against normal physics laws? As long as the water flows in it should have filled up the trap and continued to flood the pipes. To show my example: wikihow.com/Use-a-Water-Level
    – user19161
    Feb 23, 2015 at 9:56
  • Only possible way this could work is if they clogged the toilets with something with the shower hoses sticking through the trap, stopping the water from flooding the sewer system.
    – user21082
    May 8, 2015 at 17:04

3 Answers 3


Here's my poor understanding of household plumbing. Normally, your toilet (and sink, shower...) drains have a "trap" which holds a little bit of water in order to prevent the sewer stink from coming up the hole. The top of the vent pipe usually goes up to the top of the building and vents to the air (this is sometimes why in high winds, the toilet water level can bounce around).

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Lets say you flooded the room. What would happen is that the water would rush in to the bowl as fast as possible, likely removing all air until the pipe opens up significantly, probably in the main sewer pipe. Getting just beyond the trap is pointless:

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But if you got all the way to the main pipe, and out from the stream of rushing water (tricky) you'd be OK-ish (you're breathing possibly stank air, but that's better than no air)

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Perhaps a slightly more realistic scenario would be if the room was filled with a toxic gas, in that case getting just past the trap would be OK.

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  • Nick T's answer provides a good overview. Those wanting more detailed information about this part of the plumbing system should be able to find it by searching for "Drain-waste-vent system". Wikipedia has a good article: en.wikipedia.org/wiki/Drain-waste-vent_system.
    – Anders
    Mar 26, 2015 at 23:41
  • Nice answer and I think this addresses the general question of how/why you could find air in a toilet's plumbing. Note though, at least in the movie scene setup, there didn't appear to be main vent pipes. The toilets were against a short wall of sorts without any walls/pipes leading to the ceiling. I'd guess the writers used this type of explanation and separately the set designers didn't account for how it might actually work. Aug 28, 2015 at 1:31
  • "breathing stank air" that made me laugh a lot Mar 2, 2019 at 7:59

When they all crash through to the other room, one of the Kingsmen (can't remember who) tells the recruits that if they can get a pipe through the "U-bend" in a toilet, they have an unlimited supply of air.

What they're referring to is is a special type of piping "trap", often referred to as a "P-trap". The purpose is to leave a bit of water in the pipe that leads to the sewage line to provide a seal, in order to prevent the smell and potentially deadly/explosive fumes from creeping up through the toilet and into the room/building.

The idea if if they could snake a flexible pipe through the trap and up the other side, they have an air supply that will allow them to breathe for pretty much however long they need. However, given the bend is designed to prevent foul or even deadly fumes from entering the room, the safety or effectiveness of this method is highly dubious.

  • 1
    Wouldn't the trap completely fill with water because of all the water rushing down the toilet? If the room was filled with a noxious gas, I could see this being a valid trick (though breathing from the sewer vent tube is also noxious--a matter of degree I suppose), but with the 10'+ of water pressure, that toilet will effectively be flushing like there's no tomorrow.
    – Nick T
    Feb 18, 2015 at 15:41
  • Not entirely sure, but given you can add water to the bowl and it'll eventually overflow, I'd say the seal is strong enough to not casue to continually flush, but I'm not a physics major, nor am I in a position to find videos regarding such matters, so it's just my best guess at the moment. We're also talking about a movie that revels in the absurdity of the spy genre, so one could also take everything with a massive grain of salt.
    – MattD
    Feb 18, 2015 at 15:47
  • It's surely what the writers had in mind, but I don't see it working. Adding water to the bowl to cause an overflow just means gravity can't shove all the water through the trap. Actually, if you somehow get a hose to curve up in the stand pipe you might be OK, but that would be difficult as the pipes generally join slanting down
    – Nick T
    Feb 18, 2015 at 15:54
  • Unless the toilet is clogged, water added to the bowl will cause it to flush, passing water through the P-Trap and into the pipes beyond. There would be no guarantee of air (fresh or noxious) in the pipes. Feb 23, 2015 at 15:42
  • Less unrealistic than cracking the observation window by punching it. I've had more than a couple very strong guys try to punch me under water (sports). No way to get resistance or leverage to deliver the force + water resistance = laughable results. Aug 9, 2017 at 19:36

The fantastic idea, to breath from sever, came from here. This is in the same category, as breathing from car tyre. In both, the air is not simply just stinky.: http://totallyabsurd.com/toiletsnorkel.htm The situation of the original idea is not matching with the presented situation the movie. Theoretically, they can wait, until the water very slow flushed away by the several water closets, connected to one flush.: http://timesofindia.indiatimes.com/entertainment/english/movie-review/Kingsman-The-Secret-Service/movie-review/46382579.cms?tabtype=trivia But they can't breath from horizontal connected roman/commode style toilets. Also not possible: -the water with that flooding speed, is very noisy and have effect to the room temperature -the test room situated in a pool, no everyday wall can resist that pressure and thight -the observer room has to have bulletproof glass, against the pressure -hitting anything underwater, have very reduced momentum -the gym room size volume of water disappear through the observer room, this needs minutes anyway and a second pool, under the pool -the recruits we're so shocked, that nobody tried to give bare-hand CPR, or revive the fallen recruit, but they will be hostage saver agents -the fallen recruit was not fallen And this is a main spot in the movie, which was a cartoon.

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