I wouldn’t be surprised if there is some kind of interlock that would prevent opening when there is that kind of pressure differential.
If you insist, you would have an awful choice to make… release pressure suddenly so you can get to the itch fast then spend less time not breathing but probably wreaking havoc on eardrums.
Or release pressure slowly but not have air to breathe for a long time (could you hold your breath vs vacuum? hmm..)
The collateral damage to skin and ears and eyes would be pretty bad, I think.