^People don't sound like that when they die, I noticed this after watching someone actually die. My guess is that that was the VA's best take. It reminds me of how voice actors/actresses make death sounds but sounds like they're gonna orgasm because he/she might suck at death sounds.
That's probably more or less exactly what this is. Just awkward voice acting. Unless Stanley has some sort of weird burnt out morgue room fetish where he likes to wank off underneath bloody blankets near annoying puzzles. Which given how creepy the dude was about her, maybe that was the case. But not really hah.
It was also insinuated the guy was killed. Honestly, I never once thought it was anything other than a death rattle, struggling to breathe, in pain or whatever.