Logic Riddles

Question: A woman is in the hospital for a routine procedure. The doctor leaves the room locking the door before he goes, the woman is alone. The doctor comes back to find the woman has died and there is another person is in the room. The door was still locked.
How is this possible?

Question: You have 2 coins that add up to 35 cents. One of the coins is not a quarter.

What kind of coins do you have?

Question: You put me on a table and cut me, but you don't eat me.

What am I?

Question: What melts in a freezer?

Question: Travel a mile and I will change.
Travel a million and I will end as I started.

What am I?