Scorpion - Extinction - Review: Everything is Absolutely Genius

The geniuses are back at it in "Extinction." Season four of Scorpion picks up during the infamous "morning after" moment. Walter and Paige have gotten together. Now they've just gotta stay that way.
The first full day not lost at sea has Sylvester and Ralph dropping in on the Warlock's Chest, where they're greeted with a makeshift shrine to Sly, complete with his four-line, misspelled obituary in all its glory. Toby and Happy are packing up for an impromptu honeymoon to Santa Barbara. And Walter and Paige? They're just trying to figure things out. Unfortunately, no one's getting very far because it seems the world might be ending. Oh, and the only person who can help them save it is ex-team member and certified sociopath Mark Collins.

So, Team Scorpion picks Collins up for a field trip from the joint and heads to Northern Norway to plug the methane holes that are causing earth's temperature to rapidly warm. Simple, right?
For a moment, it seemed like it. But then Sylvester and Happy, who have climbed down into some Arctic ice hole discover they're breathing in methane. Happy's telling a joke. And Happy only tells jokes "once a year," so it's not a far jump to realize the methane is causing them to lose their marbles. Collins realizes this too, panics, and accidentally knocks Toby into a hole they've drilled in the ice. Simultaneous rescues see Paige pulling Happy and Sylvester out with the truck and Collins getting in the water to pull out Toby. Unfortunately, in the middle of the rescue, Sly loses his wedding Band-Aid, which knocks him more then a little off-kilter.
Wedding Band-Aids aside, everyone's okay, but now Happy kind of wants to kill Collins for knocking her new husband into the freezing depths of the Arctic Ocean. Being that the last time Toby and Collins met, Collins tried to kill him, it's understandable that she isn't convinced the whole thing was an accident.
Unfortunately, now the methane's about to ignite and blow up most of Norway. This leads to one of those seriously crazy lines of logic Scorpion's known for, when it's decided that Cabe will drive the truck into the ice hole, and bail right before the truck flys in, which will hopefully puncture the ice and dowse the methane. Except to know exactly when to bail, one of the geniuses is going to have to ride with Cabe and do the calculations on the fly. Collins again volunteers to put his life in danger.
The stunt only half-way works. Cabe makes it out and the explosion is stopped. But, Collins' coat gets stuck in the lead up and he can't jump. Cabe, ever the action man, does an Indiana Jones like jump into the ice pit, grabs Collins and is hoisted back up right before the truck falls to its doom.
Things seems to be looking up. No, the methane holes aren't completely plugged, but they've made the time to bring in new supplies. As the team gets ready to hang out up north and wait, while Cabe runs back to LA and throws Collins back behind bars, Walter jumps on the truck and breaks out in song. Like Happy's jokes earlier, this can only mean one thing. The methane's back for round two.

Random Thoughts:
-Sly's whole subplot of feeling like his life hasn't amounted to much after seeing his obituary was heartbreaking, especially his line about how marrying Megan was the best thing he ever did. Would it have really killed his Warlock buddies to throw her name in the obituary?
-I'm not completely convinced Collins is as reformed as he says he is. Yes, he risked his life for the team several times, but that whole ongoing inquiry into Walter and Paige makes me think all he really wants to do is stir up trouble.
-Speaking of Collins, I thought Cabe making him wear the dog-like shock collar so he couldn't escape during his visit to the outside world was pretty funny.
-That musical number was hilarious and terrifying all at once.
Do you think Collins is really redeemed? Are Walter and Paige going to go "extinct?" Let me know what you think below!