Arnie's body double making same noises as Arnie

I saw this movie for the first time last night and I noticed that the first guy who is re-animated starts making grunting noises exactly in that Arnold Schwarzenegger voice. Then I come here this morning only to discover that guy was played by Arnie's body double in Terminator movies.

Was he immersed so much in that Arnie role that he couldn't let it go anymore?
I loved the movie by the way. The final 15 minutes were absolutely insane. Never have I thought I'd see a mad scientist holding his decapitated head in his hands in order to go down on a woman. That's what I call HORROR. You won't see anything like it nowadays.

ENOUGH from the clown!!!!!!!!