[LunaTheHamster1]

it is my understanding that vets in the Uk use a gas chamber, then injection. I believe the Injection straight into the heart is inhumane. I don't believe you can be with them either if they are gassed first, but for me personally I wouldn't want to be.
I think it's a fine balance between quality of life and knowing when the time is right to put to sleep. Whatever we end up doing, we are all doing it with the best intentions as we don't want our hamster/other animals to suffer. My heart goes out to you and your hamster.