This week's overarching calamity is a car accident involving a gasoline tanker, which is then compounded when one belligerent gas-soaked victim decides to go outside and have a smoke and a lot of things blow up. The first two patients brought in are a married couple with a 10-year-old son. The son is okay but Dad has massive cardiac issues and Mom has a brain hemorrhage, so they are both rushed into surgery. Owen takes the kid under his wing, and they bond and it's very sweet but also a reminder of the one major issue that exists between him and Cristina. Because he gets attached to the kid, Owen kind of freaks out at the course of action that Cristina decides on for the dad but she reminds him that no matter what the situation of the patient, she's going to do all she can to save them.

Owen tells the docs that they can't play favorites and keep working with the same interns, so Heather joins Smash and Derek on the mom's brain surgery. Heather is nervous and desperate to impress Derek while Smash is secure in his role as teacher's pet and advises her to just give it time and one day Derek might come around. But when he drops a tool, she catches it and impresses Derek with her lightning reflexes to the point where later at the desk Derek starts throwing things at her unexpectedly to see if she can catch them. (She does.) When they go back into surgery, Derek decides to let Heather have a chance after afterward boots Smash for a few days. At the bar that night, Smash tells a surprised and confused Heather he knows what game she's playing and he won't go down without a fight.

Is Grey's now being sponsored by TED? In yet another episode that touts the conference, Callie is preparing to fly out and give a speech. As has happened to her before she's totally nervous and when she practices on Arizona she's stilted and boring. She gets busy with too many ortho surgeries from the crash and ultimately has to cancel her trip but Arizona tells her that this will just give her a chance to spice up her speech for next year. Callie is totally offended at the suggestion that her speech needs spicing, and Arizona realizes that she just accidentally crapped on the best thing to happen to Callie in a while. To make up for it, she and Richard arrange for Callie to speak via videoconference. Once Callie is in front of the camera, she puts down her notes and speaks from the heart, and all is hunky dory.

One of the victims brought into the ER is none other than Hot Paramedic Matthew, who threw himself in front of a kid during the explosion and now is somewhat barbequed. Honestly, I'm surprised he wasn't clutching orphaned puppies at the same time, given how unbelievably perfect they are making him. Jackson winds up having to tend to his burns, which is awkward for both of them since a lot of the burn is on Matthew's ass, and even more awkward for Jackson because Matthew doesn't know about his and April's history.

April then takes care of another patient, a pregnant woman in such bad shape that they have to deliver the baby, which gives Alex plenty of time to be shitty to Jason, who in turn is getting really tired of it. April then does the surgery on the mom, but a while afterward, the mom winds up dying. In the meantime April met the woman's husband and heard the story of how they wound up together, which seems to show that the universe intended them to be together and gets under her skin with regards to her own recent romantic history. Once the woman dies, April is really affected by it and has a bit of a breakdown. On Jackson's shoulder. Which almost leads to a kiss. (They are saved when Alex walks in on them.) It all seems to make her start thinking twice about her relationship. But when she goes in at the end of the day and begins telling Matthew about her day, he thinks she's trying to say she loves him and he tells her he loves her back, leaving her even more conflicted.

In the midst of all of the tanker explosion crash victims a woman (played by Sarah Chalke) brings in her son, convinced that something is seriously wrong with him. She first enlists Princess' help since that's who she saw a week earlier, so Princess runs tests and they show that the kid has strep. Sarah takes him home but is soon back, and when they can't find anything else wrong with her son they call over a psychiatrist, wondering if the problem is actually with her. As she's melting down Mere hears it and offers to do all she can, since she can sense as a mother herself that Sarah's instincts could be right. Sarah pulls out a bunch of notes with all of her internet research and Meredith goes through all of them, ruling out all of the various diseases. At a loss, Mere finally has to send the kid home since they can't find anything wrong. Before she discharges him she goes through all of the labs once more with Princess and when they discover the strep result was a false positive, she realizes that the kid has a rare illness called Kawasaki Disease. They manage to get him the treatment at the last possible moment, and he winds up being okay. Mere, inspired by seeing Sarah fight so hard for her child, then gets Zola and visits Bailey in her fancy new genome mapping lab so that they can both be mapped -- Mere can then learn important info on Zola's genetics, and she can also finally learn if she's got the Alzheimer's gene.