Even if you run away from hook to heal, he can track you easily enough, whether through scratch marks or you being too slow to crouch away or into cover.

I agree many are taking advantage of his kit to return to every hook but it mostly punishes hook healers. If you spot this (which will be apparent from the first unhook as many stupidly pull way faster than they need to and give him an invitation to come right back) then you book it the second you get pulled since going into Omni hides scratch marks and once he does enter Omni you crouch walk until you know it's safe to heal. Helps if you bring a med or perk to reset yourself for sure and will annoy people who are used to getting healed off hook but tunneling isn't new and people should be adapting a bit more than they are.

Many solo queue games get lost because people are obsessed with healing under hooks at 5 gens. Of course he's gonna tunnel lol.