What is the test for claiming that a statement made during an interview was involuntary?

expressed that he was willing to "just . . . tell you guys what . . . happened . . . ." (Cf. People v. Villasenor (2015) 242 Cal.App.4th 42, 65-66 [defendant unambiguously and unequivocally invoked by telling the detective to take him home 13 times in 14 minutes, trying to retrieve his phone from the detective, repeatedly telling the detective to call his parents, and referencing his "rights" in demanding his parents].) The trial court correctly concluded that the officer's decision to continue the interview by inviting Bock to "go ahead" was not a violation of Bock's Fifth Amendment rights.

b. Claim That Statement Was Involuntary