[RWebb]

yes, it looks like a vole - they are mice tho

it probably climbed to get in - most or all species do - some voles are completely arboreal and get eaten by Spotted Owls

BTW - spray the are with bleach and never NEVER touch a dead animal with your bare skin - there are many nasty diseases that they or their fleas can carry

AND the fleas can & will jump a few inches to find a new host (you)