My reaction while watching the game live was that most of the (now ten) sacks were on John Beck. Even when linemen get beat the quarterback is expected to have an ability to react to pressure and either make plays or at least avoid sacks.
Below are a selection of plays including not only the sacks but also a number of occasions where Beck was hit or pressured. As you will see the responsibility varies - Beck showed simply horrendous pocket presence, but when his blockers weren't busy losing physical matchups they were miscommunicating and blowing assignments. It was quite a mess so... enjoy.
3-3-WAS 27 (13:53) J.Beck pass incomplete deep right to T.Austin [A.Moats]. Thrown behind receiver along sideline at WAS 45.
Montgomery fails to adjust to a tackle-end stunt and allows the inside penetration. Beck takes a seven step drop and is already starting his throwing motion when the DE bursts free, so this one definitely goes on the O-line.
3-8-WAS 28 (2:27) (Shotgun) J.Beck pass deep right to L.Hankerson to BUF 49 for 23 yards (T.McGee, L.McKelvin). Caught in flat at WAS 48.
Pressure with a bit of contact, but I don’t think Beck goes down so it may be a stretch to call it a “hit.”
Beck takes a five step drop from shotgun. A Bills DT aligns wide left and drives Brown into the pocket, but Hankerson is Beck’s first read so he gets the ball out on time. The pressure actually came from blitzing safety on the offensive left. Helu identified the blitz well and picked him up but was to passive in is block and let the guy run through him.
A side note: clearly a pass cannot be both "deep" and "in the flat." This scorer showed his confusion over just what the flat is throughout the game book. He's also a little confused about which short passes to running backs are screen and which aren't.
2-6-BUF 45 (1:13) J.Beck pass incomplete deep middle to L.Hankerson. Overthrown, receiver at BUF 5.
Beck takes a five step drop. Cook is driven back from a one on one matchup with the DT and Beck, who is fixated on Hankerson downfield, does not slide to open a passing lane and instead has to throw without stepping into it. This seems to contribute to the ball sailing high, but I also suspect there was another route miscommunication here as it looks Beck was throwing a straight go route but Hank bent inside on a skinny post.
3-5-BUF 26 (13:08) (Shotgun) J.Beck pass short left to F.Davis to BUF 16 for 10 yards (G.Wilson, B.Scott). Caught in flat at BUF 17.
This play ends up working out but it was nearly disastrous. Three step drop (really three and a half – more on that below) from shotgun. Montgomery loses the leverage battle and is pushed back into Beck’s face. But a Chester-Cook double team neutralizes a DT and both Locklear and Brown, although they give ground, force their guys upfield enough that Beck had a pocket to step into. Rather than sidestep the pressure allowed by Monty he throws over it without setting his feet, and ends up forcing it to Davis. It is tight coverage and a DB jumps in front, very nearly picking it off.
However, I think Terrence Austin hung Beck out to dry here. He starts out aligned wide, then after a signal from Beck motions inside of Paul, who is in the slot. The slot corner is tight on Paul (a good blocker) but soft zone coverage leaves no other DB’s near the line of scrimmage. As soon as he takes the snap Beck takes a half step (hence my parenthetical note above) and looks to his right as if he intends to fire it straight to Austin and let him run behind Paul, but Austin releases into a route forcing Beck to go into a regular drop. It looks like Beck had a plan here but Austin didn’t pick up on it.
1-10-BUF 16 (12:30) J.Beck sacked at BUF 22 for -6 yards (sack split by N.Barnett and A.Moats).
Bootleg. The playside DE slips so Beck has plenty of time to set up. He sees no one open, but he hesitates. The options are to throw it away, or decide to run earlier. He picks the worst possible approach and commits to run too late, giving up an unnecessary sack.
3-16-BUF 22 (11:48) (Shotgun) J.Beck sacked at BUF 31 for -9 yards (J.Byrd).
Beck had no chance on this one. He is trying to hit Davis immediately in the flat (he was the rear man in a trips bunch, so he would have had two blockers and room to run) but a safety blitzes from the backside. Helu is crossing the backfield, briefly hesitates before releasing into a route in case he needs to help Brown against the RDE, and somehow doesn’t notice the safety flying right past him.
3-7-WAS 18 (7:52) (Shotgun) J.Beck sacked at WAS 11 for -7 yards (M.Dareus).
Beck takes a three step drop from shotgun, but then spends another three full seconds going through his progressions and takes no notice of the gradually developing pressure. Locklear does eventually get beat around the edge, but he worked his DE well upfield and Monty had the DT pinned inside, so there was plenty of room to Beck’s left for him to either run for it or take a slide step and reset to throw.
2-3-WAS 27 (1:26) J.Beck sacked at WAS 20 for -7 yards (D.Edwards).
Beck takes a three step drop from shotgun, but despite looking straight at the LDE as he beats Brown’s cut block (in addition to the three step drop the two cut blocks on this play are a dead giveaway that Beck was supposed to get rid of the ball immediately) he bounces a couple more times and, while he initially has an escape route to the left he uses up his time and falls prey to the DT who overpowers Monty.
2-17-WAS 32 (8:24) (Shotgun) J.Beck sacked at WAS 27 for -5 yards (C.Kelsay).
Three step drop from shotgun. Locklear gets beat around the corner, but Montgomery has the DT sealed in the middle so Beck has a large and obvious escape route to his left. Instead he tries to slide to his right where he runs into the very same DT whose penetration left the left side open.
2-10-50 (5:08) (Shotgun) J.Beck sacked at WAS 41 for -9 yards (Sp.Johnson).
Beck takes his five step drop from shotgun then remains in the middle of the pocket and bounces several times apparently waiting for someone to come open, with no awareness of Locklear again being beat on the corner. He does no step up, he does not throw it away, he does not escape to his right.
4-4-BUF 44 (3:50) (Shotgun) J.Beck sacked at BUF 44 for 0 yards (sack split by M.Dareus and D.Edwards).
Montgomery fails to adjust to a stunt again. Beck tries to escape up the middle but is chased down.
2-4-WAS 30 (2:56) (No Huddle, Shotgun) J.Beck sacked at WAS 27 for -3 yards (M.Dareus).
The DT escapes from Brown’s block and pursues Beck on the bootleg. Beck finds no one open, but he is well outside the pocket so he only has to throw the ball past the line of scrimmage. Instead, he runs himself straight into a sack for absolutely no reason. This one is just completely indefensible.
3-7-BUF 14 (:53) (Shotgun) J.Beck sacked at BUF 24 for -10 yards (K.Morrison).
Sack off a (sloppy, again – though that’s not the cause of the sack) three step drop. The line fails to adjust to a complex blitz. The Bills rush six against six Redskins blockers (linemen plus Helu). Locklear fans out wide against a linebacker. There are only two down linemen; one is shaded on Cook's left shoulder and the other is head-up on Chester. They stunt and the guy over Chester crosses Cook's face and attacks Monty. The problem is that Cook follows him too so they end up double teaming the guy. Chester is stuck on the other DL. With three linemen blocking two rushers, when a DB comes through the left A gap on a delayed blitz Helu has to pick him up (working inside out, correctly) and ignore a linebacker who takes advantage of the wide rush against Brown to blitz through the right B gap. Beck goes down.