Sounds not good. If I am correct, exit capsule is used instead of exit bag in this project. If I understood correctly it works like this, you go inside the capsule and release the liquid nitrogen. The liquid nitrogen turns into gas and is replaced by air inside the capsule. Since nitrogen is homogeneously dispersed in the room air, how do we push O2 out and fill it with N? With this method, the O2 in the capsule will decrease at a very slow rate. How many liters of N per minute does the transition of liquid nitrogen to gaseous mean? If N is homogeneously distributed in the capsule, how do you know how much O2 you have pushed out? If I'm correct, this would cause unconsciousness to take a very long time and cause tachypnea. The fact that someone is conscious of being in that capsule to die, and that comes with the psychological pressure, seems like a pretty disturbing scenario. In the classical inert gas method, almost 100% nitrogen or helium is inhaled, after removing all the air from the lungs. It allows it to work fast and be peaceful. The capsule does not seem to meet these requirements.