Yes you can! [ Im not sure, but its a ... ? Neutral tempature pocket of space from what I understand within the bag of holding so Mizuki just feels... An emptiness - a lack of heat. But no presence of something making it cold either - if absence of heat is cold... But like.. Its just... Neutral. ]

O-Oh you can... I-I would not go inside though... F-From what I understand you need air to breathe and there is no air inside.