Probably because Olivia's making a big hairy deal over it, Etta asks if she wants it back. Olivia laughs and says no, but does ask to see it, so Etta hands it over. Olivia turns it over in her hands and says, "You know, your father used to call this 'The bullet that saved the world,'" and Etta stares at her uncomprehendingly, but there's no time for Olivia to explain that "This used to be in Mommy's brain" because she gets a message on her phone alerting them that the lab's been compromised. Cut to Broyles surreptitiously putting his phone away and acting all non-molish as he strolls Observer HQ.
Etta and Olivia run into the lab to alert the others that the Observers know they're there. Peter wants to know who told her that. She hesitates, before saying only, "Somebody I trust." She says they don't have time, and sure enough we can see the Loyalists already outside cutting through the chains and locks.
Walter isn't hearing it though, and says they can't leave the lab: "Without the tapes, we have nothing. Forget the blueprints, forget the rocks from the mine, forget whatever is in the tomb; none of it means anything without the plan. There goes the world. The world ending."
Not to be outdone in the doom and gloom contest, Peter says that once the Observers see they've been there, they'll never be able to set foot in the lab again. Olivia comes up with the brilliant idea that they'll re-amber the lab. Thus, even though it appeared that the Loyalists were maybe five seconds outside the door, when they get in all trace of the last couple weeks of their work has been erased -- I guess dust has been added to everything -- such that it takes the Loyalist soldier just a couple of moments to determine that there ain't nothing here but an ambered lab and it's been that way for a long time. Windmark and Broyles are watching via special Raid-cam. Broyles does his best not to look too relieved.
After the commercial break, we see the Loyalists stomp out of the lab and Astrid pops out of her hiding space in an air duct. She does that thing people do on television and in movies where as soon as the bad guys are off-camera, they pop out of their hiding space and stomp around like there's no chance anybody ever says, "Oh, hold up, guys, I forgot my phone" or whatever and comes back. She's got the amber laser with her and she heads back into the lab.
Meanwhile, Windmark is griping about how no one has been in that lab, and that the reading from the prisoner was deceptive. Broyles asks how that's even possible and Windmark turns on another little holographic device; this one is of Etta: "Somehow she hid her thoughts from us, deceived our readings. Perhaps others can as well," says Windmark. He does that head-cocking thing too, but just for a moment -- that thing where it seems like he might be reading Broyles.