An awesome steam explosion would be... well... awesome, so if you can find someone to do that for you I would definitely do so. If not, oh well.
Everything looks really excellently detailed and I really like the overall look and feel of the outdoor areas, but I have to say that the outdoor stuff makes point C look a little blah to me. My suggestions:
1. The lighting keeps things illuminated well enough (as far as I can tell viewing the screenshots at full screen), but there's nothing particularly spectacular there. If there's any way to spice up the lighting, make it more dramatic, even bust a hole in the roof to let some sunlight in that might help.
2. The concrete seems pretty overpowering. The wooden structure on the left of the screen helps to break that up really well. If you could convert some of the concrete structure into wood it would probably help make the entire area feel a little less bland.
3. Steam? Yeah, steam is nice and all... but wouldn't highly toxic deadly poisonous gas be a much more significant thing to capture/blow up/defend? Turn that gas green or orange or something and add some lights down there to make it glow a little. There, your cap point just went from pretty cool to oozing with total awesomeness.
EDIT: Here's a very very quick example of what I mean regarding #1 and #3:
I jumbled a lot of lighting ideas in there just for examples, but I wouldn't necessarily use all of them together.