I like the speech bubbles: they add to the vividness, giving life to the characters. Most of the speech is good and natural, e.g. on p64
"Oh Fuck I can't believe this is happening! She looks like she's in so much pain..." sounds completely natural and emotionally authentic.
In a few places the speeches sounds formal, more like academic written English than the desperate thoughts of women facing the worst fate imagineable.
For example, on p73
"Do not listen to her! Take me down and I will serve you in any way you could imagine! I swear it!"
would sound more natural as something like
"Don't listen to her! Take me down and I'll do anything you want! Anything!"
And
"I'll suck your cock until your seed is drained. I'll lick and please you anywhere that you desire." is not as natural as something like
"I'll suck your cock better than her! I'll lick it... I'll lick you anywhere you want!"