Installation eats up Volume

[sacrell]

Hello there,

I'm fairly new to this, and I have experienced something rather.. unsettling with Linux Mint 14. Well, what happened?

I have 4 HDDs in my computer which runs Windows 7 x64 as main OS:

Disk 1/sda: 2TB - System drive, ~50% full
Disk 2/sdb: 1TB - Empty
Disk 3/sdc: 1TB - Encrypted on device level (Truecrypt)
Disk 4/sdd: 1TB - Filled with data, 90% full. Slow 5400rpm drive.

When I tried installing Linux Mint 14, I downloaded the ISO and put it on my USB thumb drive with Universal USB Installer. I then booted from it and went with the first option, which is to install Linux besides Windows 7 and automatically create a dual boot. I noticed it didn't say right away where exactly Linux was going to be installed, but I figured I would be told soon enough, so I clicked the Install button. Well, I wasn't asked anything minor like that. Instead, the setup went straight ahead and simply started making itself comfortable on disk 4, repartitioning and deleting the data stored on it. I tried stopping the installation when I noticed the setup said something about formatting sdd w/o having asked me anything at all. (There isn't even a button to cancel the installation, just forward/backward. However, right-clicking the taskbar did it.) The installation was stopped, but even the little progress it made rendered the data on it unreadable. I might be able to recover most of it with testdisk or something, but that is not the point.

Rather, my point is: Why the rainbows does Linux Mint 14 choose a disk at random (even a data-filled one at that!) and, without asking, just starts overwriting stuff?
Of course, I realize I might have unknowingly done something really stupid to make the setup do crazy stuff, but I find this hard to take. Could you please shine some light on whether or not this is intended behaviour and/or how to prevent the setup from committing such cruel acts?

Also, if there happens to be a standard procedure to recover data lost this way, I'd kinda appreciate to know.