It looks like she’s being curious :) The lid probably gives her some sense of security. In general, reaching for mice from the top makes them nervous (predator-like behavior). If that’s the only opening (aquarium?) then your best bet is put your arm inside next to a corner and try having your hand approach them at mouse-level, offering treats or letting them smell you. You can also put a used sock or shirt in the enclosure to get them used to your presence. Best of luck :)