I want to look at this dream in two different ways, since it's such a big chunk to take down. First, we'll look at the themes. Second we'll look at the characters and details. I'll try to keep the characters etc. within each theme point. Oh, and as the realms are split, I'd say that your subconscious is pointing out that what happens within yourself (one realm), is expressed without (the other realm). It's like if you bottle something up long enough you become bitter.

In the first part, it seems like everything is about you exclusively. Like watching a movie of yourself in costume...
:: Themes ::
- Town is ruled by an evil lady.
The town is typically a depiction of your psyche/personality. It's where all the different characters interact/reside (and each character is a part of yourself). The first thing you note, though, is that an evil lady/guy is ruling the town. that she turns to a he I'll address at the end. For now we need to see that this is a shadow self (a personification of the worst things you see in yourself, since you chose the word "evil"). And we need to address that you see this part of yourself as ruling the rest of your psyche. Something's taken over, and the first thing to ask is "What is it about yourself that you hate, and how is that part of yourself managing to rise to the surface?" In dreams, one of the goals of the subconscious is to allow ourselves to face these things that we can't do in the waking world, so the next question is "Why do I hate this part of me? What makes it bad?" But you still have to accept it as your own, and make it something positive, so you finish by asking "How can I take this flaw and turn it into a strength?" set these answers aside for later reflection.

- Storm looming close, hinting at destruction.
The key here is that there is some external catastrophe approaching, which has nothing to do with the evil lady. It's something that could be either a situation in your life, or a conflict you are having either within yourself or with someone else. Based on the second realm's overlap, I would hazard a guess that it has to do with your ex and you having to choose whether to stay close to him or not. The storm tears a plane apart. What in your life are you seeing being threatened by some rising/looming conflict? What will be "torn apart" by this conflict?

- Transit bridge is damaged/clogged.
Either way, the crash blocks a bridge connecting the town to the surrounding area (as you are connected to the world - this is the imagery of how you relate to others and how you interact with others, not simply a physical blockade between you and the rest of the world). How will the damage from the conflict keep you from being able to connect/interact with others? What sort of cleaning up is going to have to be done?

- Evil lady is trying to kill male friend with debris.
So now we see the evil lady again. This time she is targetting the "male" friend of yours. Up until now you have made no real mention of your ex's alternate character, but here we see this male character that ends up not being the ex. As every character is an aspect of the dreamer, I have to say that he is the expression of your masculine traits. Interestingly, the only other female character aside from you is seen as evil, and the male character is seen as a victim. What about your feminine side do you see as bad, and what about your male side do you see as submissive/vulnerable? It seems that you feel your vulnerability is being threatened, and since it's a boulder from the debris that is being cleaned off the bridge, I'd hazard a guess that you fear the clearing of damage is going to bring up something that you've been keeping back. The vulnerability and damage caused is what you fear will lead to this boulder wreaking havoc and eventually killing the vulnerable part of yourself.

- Friend dies, despite hiding out.
You've hid this friend, and in hiding, he and the guy that ends up being your ex were playing games. (Did you not take your relationship with your ex seriously, or did you see your ex not taking it seriously?) Since this is still all about you, what are you not taking seriously about yourself? Is your hiding away from what you fear will destroy you really just you playing at trying to avoid pain? A thought here - by destroying the vulnerability of the victim, you may actually end up with a cold calloused outlook on things. Tread carefully and remember to keep everything in moderation.

:: Second Realm ::
- Evil lady is now male...
Who in your life (that's a guy) do you outwardly detest? What makes him so terrible and how do you see that in yourself? The evil lady is the negative things within you, but we project those things onto others causing us to not like certain people we meet.

- One male friend is female, the other is an ex...
As the ex seldom shows up in the first realm, this is irrelevant... However, the female eventually dies. What traits do you see yourself and this female friend sharing? Same rule of projection applies to positive traits. These shared strengths and positive traits are what you may feel are being threatened by your shadow lady.

- Premonition of something bad going to happen...
I see this overlapping with the storm in the first realm. You fear that something is going to go wrong and you link that to a distrust toward this dictator man. The man and the evil lady are one and the same, so this is you recognizing the projection.

- Trying to decide whether to leave the ex's house or stay...
Was this the case with breaking up with him? Were you torn between wanting to stay or leave? This seems to fit in with the plane in the first realm, as it was "torn in half". You see here that regardless of what you pick, there is still damage that will happen and clean up to be done.

- You are in a ditch. A long trench...
Would you call this "being in a rut"? That very well may be exactly what it is - the subconscious showing you stuck, unsure of where to go next or possibly even stuck at where you are.

- Female friend dies in male form ( I say this because the subconscious has already shown you the death, so you probably just put two and two together and inserted the male form since you already knew he died)...
I find it interesting that in the first realm, your ex doesn't show up until almost the end, and then in this one the other friend doesn't show up until almost the end. This further tells me that the other friend is what you fear will happen to you because of this great conflict. The finale here is you looking at yourself, having to face the damage of whatever the conflict might happen to be.

This was a really heavy dream, with what seems a bad ending. I'd like to leave you with a couple of thoughts...
::: Dreams about yourself are almost always never written in stone. You have the self revelation open to you, all you have to do is take the knowledge and prepare yourself to avoid the worst.

::: More importantly, death in a dream is never literally about death. It's transformation and the changing into something else. This male version of you might simply be prone to change after the conflict blows over. The key is to make the change a positive and healthy one.