Don't feel discouraged, some hamsters take longer to tame than others. You are doing just fine, taking treats and sitting on or even near your hans is a huge accomplishment. I think it is in their nature to try to get out of new places such as the bath tub. I personally pick mine up after about a week. Try not to be scared that they are going to bite you because they can sense you are nervous and it makes them nervous. Just move slowly when you go to pick him up. I always let hamsters smell my hands, by offering them my knuckle area not the tips of my finger. I work with hamsters everyday and I have 12 Syrians including two eyeless whites and the only one that has ever bitten me was a very sick little boy who did not want to take his medicine. You will be able to gage his mood when you hold out your hand, if he jumps or moves away or goes into the angry bear position don't try picking him up and give him a few minutes to calm down. Good luck, you won't need it though, you are doing great