Madness.
This is the same Nani, that went down, got up, ran round to the ref, and then went down again as if shot?
No wonder they thought he was trying it on, and he probably was.
Its a bit obvious he wasn't trying it on, as for getting up, yes he got up to complain, I really hate this excuse, anyones whose ever REALLY felt pain will realise its not a constant singular thing, pain can kick in instantly, or quite frankly you can know somethings wrong and feel nothing for a while thats life.
You can have a 3mm paper cut in the wrong place that stings all day long, or a 2inch gash in your hand, can see the bone, the skin is peeled back, its bleeding like hell and you can't feel it, pain is odd.
He also most certainly didn't go down again "like he was shot", he went and had a go, Gerrard shoved him, lightly but he's basically on one leg, off balance, and he goes down really slowly, not at all like he was shot, and Gerrard can look straight at him and blood coming out of his leg, but ignored it and had a go.
As for Rafaels, I hate the guy, completely, but he's got one foot on the ground, his weight on the ground, his leg on the ground is bent significantly, and is flat to the ground, the other leg is flailing but its also significantly bent.
Caragher, straight leg, lots of speed, no weight on his back leg, ALL weight in his LOCKED forward leg which also, significantly catches Nani's front leg which has no where to go, theres no getting out of the fact thats VERY lucky to not be a leg break, ridiculous challenge, insanely dangerous.
Rafael's, leg bent, meaning his own leg isn't locked, theres a lot of flexibility, his weight is on the ground not locked into his leg coming down, he doesn't catch the front leg of Lucas and wouldn't have caught his front leg half way up his shin with ALL his weight.
Rafael's tackle certainly wasn't pretty but Caraghers is INCREDIBLY lucky not to break Nani's leg, Rafel's would have been incredibly lucky to even hurt Lucas, it would be a 1/10000 chance he broke his leg, they aren't close to comparable.
Caragher should have had a straight red for a reckless, dangerous, stupid foul that did make contact, Rafael should have got a red to stop players doing daft tackles, because when you mistime the one Rafael did, you end up doing the one Caragher did.