I'm on the Bath House Level trying to get Shetland and it's a nightmare!
You kill all the guards, climb in the vent, watch Shetland kill a load, then you kill some more. But the hard bit comes when you try and kill the 3 guards in the shower room. This is extremely difficult and the only way I've managed to do it is by getting two of them with a sticky shocker as they try to sneak in from the right and then shoot the third on the left of the room through the shower glass. But even then you go through the door on the other side and have to disarm the bombs at which point another guard appears and kills you. Then it's back to the beginning again to do it all again. Very frustrating - Whatever happened to the checkpoints that were in the SC 1 and 2? Any tips to get through this would be much appreciated.