I've never used the 'alias' option for an exit.
The easiest thing I think for you to do is to add a command to the room attached to the closet.
Simply right click on that room. Add command. In the box under command pattern type in whatever command you want the player to type to enter the closet. I would do something like this --> closet; enter closet; go in closet; go inside closet (etc)
Then, run a script that moves player to closet.
<command>
<pattern>enter closet; closet; go in closet; closet; in; step into closet</pattern>
<script>
msg ("You step inside the closet.")
MoveObject (player, closet)
</script>
</command>
And, if you want to the player to leave the closet the same way, just repeat above with a different command (or just create a one way standard exit 'out').