Why couldn't they just shoot Peter with tranquilizers?

They would be able to stop him without killing him. Would that have worked or were the anti-anesthetic drugs still in his system? If they were still in his system, why couldn't they just hit him in the head or something to knock him out?

"This isn't my house."
"Didn't that movie used to have a war in it?"
"I was saying Boo-urns."