Supergirl Just Revealed a Major Flaw in the Show's Foundation

White Martian showdown for a while now, and on Monday's episode, cheekily titled "The Martian Chronicles," it finally happened when M'gann's (Sharon Leal) former mate and another White Martian arrived on Earth to hunt her down for being a traitor.

Unfortunately, the episode also revealed a near-fatal flaw in The CW superhero series, which is that the security at the DEO is horrendous.

[...] she chose to return to Mars seek out voices like hers, to stand up and fight against the White Martians who believed they'd created the perfect paradise by obliterating the Green Martians for being what they perceived to be inferior.

[...] while J'onn And M'gann were getting all emotional, Kara (Melissa Benoist) and who we thought was Alex (Chyler Leigh) were engaged in a heart to heart about Kara's fear of being abandoned by her sister now that she's dating Maggie (Floriana Lima).

Unfortunately, before Kara could rectify her obvious mistake, Mon-El found someone else in the form of Kara's replacement at CatCo, and well, I don't know what else anyone expected.