How can I get outside the city gate?

As the guards have told you, you need a gate pass to get through the gate.

Try talking to the little (scared) guy in the bar.  He has some information
on a gate pass.

Oh well, a ghost stole his gate pass.

I guess that means you can't get it yourself, unless you're the ghost, that
is.

You'll need to find a ghost disguise.

The sheet from the bed in the inn (not in L-space) will work.

Now you should go back into L-space and visit the little guy at the inn.

Use the sheet on yourself to create the ghost disguise and watch what
happens.

There was a hammer in the safe.  Don't you wonder what that was for?

Maybe you can go back and ask.

Return to regular time and talk to the little guy again.  Notice that he
gives you a little bit extra information.

So use the information.

Return to L-space and repeat the ghost sequence by wearing the sheet.  This
time, now that you know what do with the hammer, you'll be able to get the
city gate pass.