If I were Samus, I'd say screw the tunnels. Litterally. Screw attack through the tunnels. If you happen to run over the twerp, he's dead. If he attacks you, it's harmless (heck, even the jaws of the oh-so-powerful queen Metroid can't hurt Samus while she's screw attacking). Use the infra and xray vision to scan for traps. Either that, or I'd setup camp in the high ground. After all, he can't win unless he kills me, and he can't do that from the tunnels unless I go into the tunnels.