You could model it in Sub-Ds, it wouldn't be too complicated, but it would be very time consuming, and the door would end up being very dense and unpractical. Your best bet would be to go with a Displacement map.
Good Luck!
www.stevenegan-cgi.com
"Your weapons are no match for ours! People of Mars, surrender!"
"Um, this isn't Mars. This is Earth."
"Earth? Earth-with-nuclear-weapons Earth?"
"Yes."
[long pause] "Friend!!"