Hi Chime. Since the cotton is clean, if they have access to water do they really need to move? It seems like they are trying to stay cloistered, shut in, and since there isn't anything that's going to harm them if they do this maybe they need to just be left alone even more (provided that they do have access to water either place the tube in a tiny outworld that has a fresh tube with water near by and and cover them both or attach a clean tube with one of those double connectors so they can take their sweet time moving and get water if they need it)
The tube doesn't look bone dry. Do they have brood? are they moving?
I don't have any particular knowledge of this species, but ants not wanting to move at this stage of colony development is normal. Only stress or danger might induce them to move, such as if the tube were bone dry, although it seems moist.
Often when people ship ants, especially tiny ones that drown easily they will put moist cotton but not water since it's hard to keep tubes from leaking in transit. Then you feel like you need to move them to a tube with water, but pay attention to what the ants are telling you by their behavior. If they aren't seeking water you don't need to force them to move. I've had a bad day with antkeeping and thinking on how sometimes doing less is MORE. Best of luck!
I'd love to see some close ups of them when you photograph them again... do you have a magnifying glass or macro lens?
Starting this July I'm posting videos of my ants every week on youTube.
I like to make relaxing videos that capture the joy of watching ants.
If that sounds like your kind of thing... follow me >here<.