"The Quality of Mercy" was the second-to-last episode of Mad Men this year — and with so much left to do, the show delivered an episode that was unusually brisk for its ponderous sixth season, as a series of long-brewing personal conflicts finally came to a head. As it turns out, there was plenty of range in the quality of mercy depicted in the episode as the show's various characters debated how to use the leverage they have — and make decisions that are likely to have dramatic and permanent effects on the show going forward.

"The Quality of Mercy" spends a fair amount of time with Sally Draper, who finds the safest way to avoid seeing Don after catching him with Sylvia in last week's episode: Running as far away from him as she can get. Sally, like Don before her, is desperate to escape the sins of her father. But her flight has landed her not in a warzone, but in the confines of Miss Porter's boarding school.

Unfortunately, it doesn't provide much respite. Mad Men is a show about how impossible it is to escape things — our pasts, our lives, ourselves — and Miss Porter's boarding school is packed with echoes of the life Sally is trying to leave behind. "I want to be a grown-up," Sally says to Betty on the way to her one-night trial run, but the boarding school plays by the same rule book as the so-called "grown-ups" in her life: Drugs, alcohol, and casual sexual encounters.

At the behest of her roommates Mandy and Millicent, Sally calls longtime friend Glen Bishop, who shows up with alcohol and a friend named Rolo. It isn't long before Glen and Mandy retire to the back room and Rolo ineptly, fumblingly tries to seduce Sally, offering yet another unpleasant echo of thee recent revelations she has had about her father: "I've been with lots of girls. I know what I'm doing." When Rolo gets pushy, Sally complains to Glen, which leads to a fist fight that ends as Rolo leaves in a huff. But Glen isn't concerned about having a long-term problem with his friend. "Don't worry about him," he says as he follows his Rolo out the door.

Not every problem in "The Quality of Mercy" can be resolved by a simple fistfight. After a season's worth of speculation, we finally have the real story on The Talented Mr. Benson, who's assigned to team up with Pete to take on the Chevy account when Ken Cosgove decides he has had enough after a hunting trip that went very, very wrong. (Only in Mad Men would a character being shot in the face be a minor footnote in an episode.) But Pete is newly uneasy around Bob, who came on to him in last week's episode, so he enlists Duck Phillips to help lure him away from Sterling Cooper & Partners. But Duck's preliminary digging sketches in what little background we have on Bob: A mysterious liar with no real credentials who has shed his rural past through a combination of good looks, charisma, and talent, and pursued his dream of becoming an ad man on Madison Avenue.

Sound familiar? The parallels to Don Draper are striking enough to Pete Campbell, who responds to Duck Phillips' incredulous "I've never seen anything like this before" with a bitter "I have." Given Pete's status in the firm — and Bob's relatively tenuous place in it — it's probably enough to have him fired. But let's review what happened the last time Pete Campbell risked his career by revealing the shadowy past of a professional rival:

For all his faults, Pete is too smart to make the same mistake twice, and he uses the information he's gained not to burn a bridge with Bob, but to build a new one. "I don't know how people like you do it," says Pete, before apologizing to Bob and laying down a set of ground rules to smooth over their personal and professional differences.

Which raises the question Mad Men has been quietly teasing all season: Is Bob Benson the next Don Draper? It's hard to say — but if "The Quality of Mercy" is any indication, Bob Benson might want to avoid the path that would turn him into Don Draper 2.0. We're 12 episodes into Mad Men's sixth season, and in case the message somehow wasn't clear by now, "The Quality of Mercy" spells it out yet again: Don Draper is a petty, egomaniacal shell of a man who'd happily torpedo a major account over a minor point of pride.

The catalyst for Don's rage in tonight's episode was the palpable sexual tension between Peggy and Ted Chaough, which is close to boiling over (despite this season's "The Better Half," in which Ted called for an end to their flirtation). After Don and Megan run into Ted and Peggy at a screening of Rosemary's Baby — line up here, Sharon Tate conspiracy theorists — Don works up a Machiavellian scheme to get back at Ted for developing a relationship with his one-time protégé, and to get back at Peggy for being so open to it.

Don's revenge was built on humiliation. After seeing Ted and Peggy's enthusiastic pitch for a Rosemary's Baby-inspired commercial for St. Joseph's Aspirin — a pitch that's tens of thousands of dollars over the budget allotted by the company — Don calls St. Joseph's to warn them about the increased budget, which prompts an emergency meeting. (Never mind that the expensive commercial is exactly the kind of calculated risk Don loves to make when it's his idea.) At the meeting, Don tells the client that Ted has a personal reason for investing so much in the campaign — and he makes sure the not-so-subtle subtext is clear to both Ted and Peggy before he reveals the lie he has invented to cover for them: That the commercial was the final brainchild of recently deceased partner Frank Gleason, which is enough to earn a vote of sympathy and another $10,000 from St. Joseph's.

The tricky thing about "The Quality of Mercy" is that Don, whatever his motivations, is actually right about Ted and Peggy. "Your judgment is impaired. You're not thinking with your head," complains Don, correctly, in a tete-a-tete with Ted after the meeting; whether the Rosemary's Baby commercial is a good idea or not, Ted is far too invested in making sure Peggy wins a Clio.

In an episode packed with characters scheming to better their positions in life, which of them made the right decisions? To a degree, Sally, Pete, and Don all got what they wanted. Sally reasserted her connection with Glen Bishop and secured her acceptance to Miss Porter's. Pete reasserted his power over Bob and turned a potential enemy into a reluctant ally. Don reasserted his strength over Ted and convinced St. Joseph's Aspirin to throw in another $10,000 for the campaign.

But the episode isn't called "The Quality of Mercy" — a titled derived from a famous line from Portia's speech in Act Four of Shakespeare's The Merchant of Venice — for nothing. As Shakespeare originally wrote,

The quality of mercy is not strained.
It droppeth as the gentle rain from heaven
Upon the place beneath. It is twice blessed:
It blesseth him that gives and him that takes.
'Tis mightiest in the mightiest. It becomes
The throned monarch better than his crown.

None of the characters in Mad Men were practicing anything close to the hyper-idealized version of mercy peddled by Portia, in which doing something out of complete selflessness is the ultimate way to be powerful. But however calculated a move, I suspect Pete's decision to show mercy to Bob will pay dividends, in one way or another, in the episodes to come. And as for Don's decision to vindictively lash out at Ted and Peggy, which leaves Peggy sputtering that Don is "a monster" as the episode comes to an end? Something tells me there will be consequences for that, too.

Read more Mad Men recaps:
* Mad Men recap: 'Favors'
* Mad Men recap: 'A Tale of Two Cities'
* Mad Men recap 'The Better Half'
* Mad Men recap: 'The Crash'
* Mad Men recap: Fifty Shades of Draper
* Mad Men recap: 'For Immediate Release'
* Mad Men recap: 'The Flood'
* Mad Men recap: To have and to hold
* Mad Men recap: Sex, lies, and a ketchup account
* Mad Men premiere recap: Death and 'The Doorway'