Duplicants go through atmo suit checkpoint wearing oxygen mask

[koalasforlife]

My duplicants keep walking past an atmo suit checkpoint while wearing only an oxygen mask. There are plenty of fully fueled docks of atmo suits before the checkpoint, and I have the checkpoint set to "clearance: vacancy." When duplicants return from the area past the atmo suit checkpoint, they also ignore it and keep the oxygen mask on. I have had a few duplicants die from scalding in an area they are only supposed to access while wearing atmo suits. I confirmed there are other access points besides the one with the atmo suit checkpoint. I also watched to see what was happening and saw duplicant completely ignore the checkpoint. I also checked to make sure the checkpoint building is enabled. What should I do to fix this? 

[bialix]

I build checkpoints and docks for high radiation areas so dupes can take off their atmo suits and get lead suits instead. That was the most intuitive way for me, although ONI logic someties contradicts real-life logic.

[koalasforlife]

Oh ok that makes sense so it's basically a double checkpoint that they walk through? Thanks for your help!