My answers are assuming the tour hasn't changed in a year and a half.

You can leave early, but you'd have to do it before you get to the top levels unless you make arrangements with the guide (not sure if they'd allow it). On our tour, we went underground first, spent a few minutes on the main level, then went to the top.

The top levels are not accessible without a guide.

I'm not sure about your last question, sorry.

Thanks jent--were you able to look around the Colosseum in the main areas before your tour?

Since we'll have no time aftewards, it'd be great to tour the main levels before.

Do you remember if the tour met inside or outside the ticket collection area?

I'm concerned that if it met outside the area, if I go in and tour first I can't meet my tour guide since there is no re-entry for the ticket.

Thanks!

Our tour (I'm assuming yours is the same, but I don't know for a fact) met outside the Colosseum entrance. We got our tickets, then met our group off to the side but still in the "foyer" area, directly next to the entrance to the underground section. We were with the tour guide the entire time.

I should clarify - we were past security where we met the tour guide, just not actually inside the Colosseum walls. I can't remember who checked our actual tickets.

Oh I know what you mean. You were inside the gated area where the security check is but not yet inside the wall.....hmmm I think then you met your guide before ticket collection.

Thanks, that helps alot.