The space blanket was working just fine, thank you, and the details were between Sitwell and his doctor and/or God. Loki-- couldn't someone have told him it was Loki when they called him in?-- could laugh all he wanted, but this was a medical device and he would realize, one day, that he was wrong. Maybe it would ruin a good night's sleep for him, if Sitwell was lucky.
He was loathe to start kicking once up in the air, as much as he wanted the freedom to bolt into safety and call for immediate, heavily armed, magic-prof back-up. If the vine let him go, then Sitwell would just come down on the pavement skull-first, and while he had been assured many times that he could probably recover from the worst of skull-crushing type wounds, this wasn't the time to test that theory. He really did want to discuss this, in short, and he really didn't think he was being impolite about it. "No, don't drop, thank you," he insisted very politely to make his point, but the shooting wasn't helping to keep him calm and rational. At the first blast, Sitwell did start kicking and shouting, "This isn't a discussion!"