What if you had to switch places with them?
Inhaling concentrated CO2 is akin to burning from the inside out for any sentient being, be it a pig or a human. The pigs, in their panicked state, inhale the noxious fumes deeply, experiencing suffocation due to oxygen deprivation and convulsive reactions caused by the harsh toxins flooding their lungs.
Please leave pigs off your plate and go vegan!