1.
If you shut someone or something in a room, you close the door so that they cannot leave it.
The door enables us to shut the birds in the shelter in bad weather.
PHRASAL VERB : V n P n
2.
If you shut yourself in a room, you stay in there and make sure nobody else can get in.
After one particular bad result, he shut himself in the shower room for an hour...
PHRASAL VERB : V pron-refl P n
3.
see also shut-in