"I have been in a CS gas chamber in such kit many times. You know when it leaks. If you fit it correctly it does not."

As I said you would make a good canary. Better to use a suit designed not to leak. Especially if leaks have fatal rather than uncomfortable outcomes

Meanwhile a little background for those that are not totally bored with the fiasco.
https://theconversation.com/novichok-the-deadly-story-behind-the-nerve-agent-in-sergei-skripal-spy-attack-93562