Thread: Not rude...but there was four men in a brothel see...

I've been telling this gag for twenty years, and always get a great response...so too hard to resist putting it up here (moderators - I've told this to my Aunt Molly who is a None, so it's ok):

I'm going to tell you about four men in a brothel. I'll tell you what they're doing, and you have to tell me where they come from. Alright? Goodo.

The first fella is lying on a bed with a woman.

The second fella is coming in no, entering the no, using the front door.

The third fella is leaving through the back door.

The fourth, and last, is sitting in his car, underneath the red light.

So, where do they come from?
What I'm looking for here is well reasoned answers (for my own amusement). Replies of "I give up" will not solicit an answer! You can try to answer all four at once, or one at a time in any order.

(if you know the gag, please don't spoil it for the others)