Hermoine wanted to hand in the marauders map because she feared?

Answer 1

It would fall into the wrong hands, he would get into trouble or Sirius Black could be using one of the entries to gain entrance to the castle.

Answer 2

No, that was Harry's broomstick from Sirius Black.

[she did fear that Sirius would use it to break into Hogwarts, however]

Answer 3

black was using a passage on the map to get into the castle