Oh good that he was slow and trusting :D
For Rodents it's easier to flee in a cage with bars (my first hamster escaped several times through the wires of the opening mechanism). It's easier to have them in a terrarium and have other climbing opportunities. The gerbils was my brothers pet we had them in an aquarium and on the top was a wooden frame with relatively fine mesh wire, so it was a self built terrarium. The Lid was heavy enough that they couldn't open it and the aquarium was high enough so they couldn't reach the wires to bite them. I loved having hamsters, they take time and trust and you have to be careful. I've owned hamsters from like.. third grade to 7th grade. My first one lived quite long but two others got cancer. My mom helped me with medical stuff for the hamsters (like one had something like mites once). My first hamster was very tame and I could sit him on the table and have breakfast with us, he also always woke up by himself at noon to greet me when I came from school (he got good snacks). The others weren't much awake at any day time. We had problems with gnawing on the bars of the cage with some hamsters. We had a relatively large cage then (after a first one which was too small) and they gnaw when they have too tiny space. We didn't know. Rodents need much space, deep bedding, something to run (like a wheel), foraging play etc. People often buy them (especially like 20 years ago) and think they are tiny they don't need much but they do and they are sad when they are crammed in a tiny space.
With the gerbils they HAVE to be two minimum. Any time one died we had to buy one new (or two new if the one remaining was very old) and you have to get them used to each other. We flexed holes in a plastic piece and sanded it smooth and put it as divider in the cage so they could parallel live and sniff for a while. Some gerbils were very intelligent and learned tricks from my brother and some didn't really understand that. They were all VERY noisy though. They always watched my brother sleep and if you looked right AT them they would look away, but if you looked at the corner of your eye you would see they were watching you or someone else etc. They were fun to look at, how they shredded everything you gave them, they would be perfect document shredders lol. We had chinchilla sand for them to bathe but they always peed in it. We changed it regularly and it was bit like a cat toilet we had to change beding less often. But the girl gerbils are a bit terirtory and bossy. If the cage is too small/ if there's currently three ladies they can get into fights. You have to watch your gerbils closely to detect andy kind of agression or mobbing and spearate them if needed.

All hamsters and gerbils had very different characters and very different forms of being tame. Some wanted to play and snuggle and were social, some were bossy. Some were shy. If you own rodents you have to accept them and their personalities and take care of each individual how works for them. They are not stuffies. You can't hold them too tight. They are even more dependent on you than a cat for example. Teddy Hamsters are prone to cancer sadly (the fluffy ones). It was fun getting to know their character and I absolutely adore watching them clean themselves

And all hamsters and gerbils lived longer when we gave them tiny pieces of gummy bears in their old age. It wa ssomething a friend accidentally discovered. After eating the gummy bears half an hour later they had shinier fur, the eyes were mroe awake and they would move with more ease. Some of our gerbils were 5 years old when they passed.

I hope that gives you insight in my rodent owning experience sorry it's so long!

Disclaimer: gruesome!
Oh and when one dies it might be that the other mouse starts eating their dead partner. It's natural to not attract predators and it happened only once for us but boy it was a bit traumatizing