Episode #1.3 - S1-E3
Stupidity: Julie took Sean's phone, and we learn she cut his thumb off so she could keep it on her to unlock the phone whenever needed. This makes for a funny moment but makes zero logical sense - having unlocked his phone once, she could just remove his thumbprint and use her own instead, or disable the security entirely.
Mr. October - S1-E2
Stupidity: The two men with Hermit decide to jump down a floor into the damaged building since the stairs are gone. They're aware the structure is unstable and the ship inside is dangerous, but leap without proper rescue gear, trapping themselves with no way back up. For a supposed rescue mission, it's reckless and leaves them stuck if things collapse. (00:10:45)