Got a BoS quest to find parts to repair air purifier - need to find Air Filters in Vault 22, which I had previously been thru. Map marker shows it on Oxygen Generation level, but I can't reach it.

Anybody know the secret to get to it??

ps: This is another example of the Local Map being useless, or actually less than useless, a hindrance

From the Lab level (IIRC) there is an entrance into the Cave, go in there and follow the tunnel. It will exit you to the Oxygen Section that is sealed off.

Yes, we really need a colored glowstick mod for FO:NV, something I can use to mark locations easily.