If you set out to look for SBTC in that Bible, you would be looking long and hard in its almost 2000 pages. SBTC doesn't occur, backwards or forwards, as first letters in contiguous verses or first letters in contiguous words anywhere else in that Bible according to Don Foster. I looked in Psalms for another instance, but I ran out of steam about half way through. Foster probably did an electronic search.
Patsy undoubtedly got to Psalm 34/35 from Psalm 57. That psalm contains her life-saving line (as reported in both DOI and TOSOS) about taking refuge in the shadow of God's wings. The line before that is cross-referenced to Ps 34:22, the last verse of Psalm 34, after which come the four lines beginning CTBS. If she was familar with the phrase "saved by the cross," she would, no doubt, take the presence of those letters as a sign from God.
If the Bible were already open to Psalm 34/35, an intruder could have grabbed it for his sign-off. Patsy squelched that idea, though, and I don't think John has ever said it was possible. The Ramsey side just doesn't talk about it. Jameson says that Steve Thomas is probably lying about the Bible being opened there, which doesn't really help her case. And she doesn't try to explain why John would say in TOSOS that he read the hair-raising Psalm 34 to Patsy on her deathbed and made her cry. I don't think the ghostwriter just pulled that anecdote out of thin air.
(Second reply to fix some typos.)