" He should have known: Experimental inventions equate unprecedented effects. Howard’s words of wisdom, if you will.
/ I did try to warn you, Sir. /
And, oh, yeah, J.A.R.V.I.S.’ voice mysteriously appearing in his head.
He huffs. Story of his life. "
Or, the Mk IV ARC Reactor has unprecedented effects on Tony's biology. Tony is more concerned with the unprecedented effects Steve has on Tony's biology.