Life Signs Detector in Travelers

[Cap116]

Like the shield worn by Lucius, it's possible that Sheppard using it was all that needed to be done for someone else to use it.

However Mallozi did say Zelenka wasn't using a scanner in "Reunion" despite it being one, so it's possible that they magically used the same looking, yet not an actual scanner device.

Zelenka was also using it in "Doppelganger," when Sheppard was going into McKay's dream. so despite whatever is said, on two separate occasions Zelenka has used the Life Signs Detector without having the ATA gene. To repeat what was said above. Plot hole.