I'm not sure Arsenal did stop playing. There was only 1 defender back and he seemed to be playing on.
And I think it's Frank's old age that causing problems with his memory re a goal with 10 minutes to go, not yours.
He did get booked which by the letter of the law means the ref must show the card there and then but I'm not sure that should be the case. Liverpool had just been denied a great opportunity to score by the foul and the fact that a card had to be produced there and then denied them of a 2nd opportunity with the quick free-kick.
If it had to be the case then I'd have rather he wasn't booked and the ref allowed the free-kick to be taken.
I'm fairly sure there is no rule that the ref couldn't show the yellow card instantly, ref's make a huge deal of calling players over and in particular he made a monumental deal of talking to Sagna for ages to make it seem like play really couldn't have gone on. The whole ref's "explaining" the situation to players winds me up rotten, unless it's a 17yr old kid in his first game, did Sagna need the situation explaining to him, did he need to be told another one and you'll be off? He knew he wasn't on a card, had the leeway to make that challenge and take a card, what the hell is the ref explaining that the player doesn't know.
Unless it's a red card I see no reason to punish the attacking team, even then in a case like this it would have prevented a goal while Sagna on or off the pitch(assume he deserved a red) wouldn't have prevented the goal. Sagna in this case cynically stopped a player from having an advantage due to our defense being awol, the freekick at that stage still had that advantage, the ref took it away, it positively rewarded the cynical challenge rather than punishing it.
I don't know if ref's have been pushed into stopping quick free kicks but I've seen many more than usual being called back by the ref for no apparent reason, many when no card was involved, seems to be Europe wide from what I've seen as well. In that case all that was required was foul happens, ref whips out card, takes 2 seconds, game goes on. There is precisely no need to explain what that means to a professional footballer, if he doesn't know what a yellow card means and how he must play the rest of the game he shouldn't be on the pitch.
Dortmund should utterly destroy Arsenal, Arsenal were poor, unable to create, over run in midfield, Ozil was made to look poor, as he was largely against Liverpool, and Chelsea, Giroud couldn't offer anything on his own, he links up well but is poor trying to do a Drogba style holding the ball up or working the defense on his own.
We don't have a team capable of playing them, the only upside is that Dortmund came to Arsenal to be hard to beat and weren't trying to win 6-1, as they did on Friday. They were playing safe, playing for the draw and still won. At home they'll go for the win which will give us more space to attack and possibly Ozil will be under less pressure, but not much. While our offense should find it marginally easier, our defense will be under FAR more pressure they'll try and thrash us and frankly they are fully capable of it.
Dortmund played VERY well in the Arsenal game, they just had a very different game plan to the majority of their games and they quite easily made us play worse.
Caz/Ozil in particular don't do well under heavy pressure, Ramsey/Rosicky and to a lesser degree Arteta will get caught making lots of silly mistimed tackles against a quick offense, they do usually but it will happen more against better and faster players, those 2 or three players can't seem to help themselves sticking a foot in once the player is long gone. Will not be surprised to see all three on yellow cards leaving us less able to be physical with them in midfield. Fullbacks.... our fullbacks struggle against everyone, a Dortmund team actually playing to win, I cringe to think what Sagna will get up to tomorrow.