[Jango]

Chlorine can kill instantly.

If you want other evidence, Wikipedia says:
'About 1,000 ppm can be fatal after a few deep breaths of the gas.'

Therefore, a few deep breaths of chlorine at a concentration of 0.2% will kill you in seconds.

The chlorine concentrations in Oddworld (if it is chlorine) are probably well over 2% because you can clearly see the green colour. Therefore, it would kill you quickly and easily in one breath, as we see when Abe breaths the gas.

I've breathed in chlorine before (by accident) at a concentration of about 0.003%, and it made me cough nastily and it was rather painful. It has an instant effect. Concentrations 1,000 times that amount (3%) would easily kill you instantly.