Replacing XBox DVD drive - new drive too short

So, I am replacing the old burnt-out DVD drive from my XBox with a newer, more capable drive (modded to fit and work with the XBox).

Only thing is, the new drive is too short, and so won’t sit still in the drive bay, beign free to scoot back and forth in the drive bay.

I figured out that if I stick an empty film canister (Fujifilm, if it matters) behind the DVD drive, it was just the perfect size to make the drive stay put. I was worried that the heat inside an XBox might make the film canister melt though. Is this something to be seriously worried about? If it DOES melt, will it hurt anything inside the XBox, all presumably built to higher heat tolerances than anything I put inside it?