An AppleScript to start vim inside iTerm

itermvim.scpt

#!/usr/bin/osascript

on run argv
	tell application "iTerm"
		make new terminal
		tell the last terminal
			make new session
			tell the last session
				activate
				exec command "vim " & argv
			end tell
		end tell
	end tell
end run

I don't understand why make new session creates another terminal when this script starts up iTerm2. If iTerm2 has already been running, this script creates one new terminal and starts a session with vim inside it as expected.