@tonkatoyman - Yes, he swallowed head first. I can't believe I forgot to mention that.

@all others - The medium rat was smaller than the thickest portion of the snake. Like I said before, as soon as that damn arm was down, the rest of it was down in less than two minutes. I think he can easily handle the size of the prey. However, now that I know I shouldn't feed med. rats to adults anyway, I'll stick to small rats.