Hicks: Even on the rack the wise man is happy.

Yonge: That even if the wise man were to be put to the torture, he would still be happy.

It's important to remember that the original says εὐδαίμονα not "happy." There's a different connotation!

Trivia: στρεβλωθῇ means "stretch on the wheel or rack, to rack, torture, applied to slaves for the purpose of extracting evidence"

Hicks: When on the rack, however, he will give vent to cries and groans.

Yonge: Nor will he groan and howl when he is put to the torture.

So. will the σοφός groan or not?

The original text runs:

[118] κἂν στρεβλωθῇ δ᾽ ὁ σοφός, εἶναι αὐτὸν εὐδαίμονα, [μόνον τε χάριν ἕξειν τὸν σοφόν, καὶ ἐπὶ φίλοις καὶ παροῦσι καὶ ἀποῦσιν ὁμοίως διά τε λόγου184 <καὶ διὰ πράξεως>. ὅτε μέντοι στρεβλοῦται, ἔνθα καὶ μύζει καὶ οἰμώζει.

• ὅτε μέντοι στρεβλοῦται, ἔνθα καὶ μύζει καὶ οἰμώζει. There doesn't appear to be a "nor" here:

• ὅτε when

• μέντοι indeed, however, to be sure

• ἔνθα when

• μύζει I. (he) murmurs with closed lips, mutters, moans.

• (και) οἰμώζει (and) wails aloud, laments

So, Hicks seems to have the upper hand here. This also makes sense in the light of the sage being more affected by the emotions but also remaining content under torture.