1. Not pissing off Pontius Pilate... (j/k)
2. Prevention is better than escape.
We have some crucifix players at my academy. I find that the ones I've rolled with so far need two things to get a crucifix position. They need to trap one arm with their legs, and another with their hands or arms. They tend to go for the leg trap first. Once they have that, there are plenty of ways for them to trap my remaining arm. But if I avoid letting them trap my arm with their legs, they have to pick something else besides the crucifix.
The absolute worst thing to do with a crucifix player is to give them anything resembling a chance to trap your arm between their legs. That is what they want. Hooking the inside of either leg from bottom turtle is something I've learned (the hard way) not to do. The second my elbow advances behind the line of their knees, it doesn't matter which direction my hand is pointed or whether my elbow is bent. A good crucifix player snaps his or her knees closed on my upper arm, and no matter which way I twist my arm it only delays the inevitable, unless I can brute-force my way forward and around to take the back. They generally prevent this by cross facing me. Sometimes I can grab that sleeve near the wrist, heave the person in the direction of the sleeve to make him or her post, use my sleeve grip to pin the posting hand to the floor and go for the duck-under, but it's a brute force move and I haven't been able to make it work reliably. I have not been able to make it work at all in no-gi. In fact, my best option so far has been to not give up that grip in the first place. For me, at my present skill level, against a crucifix player, it's a mistake 100% of the time. YMMV.
Now, if I'm in turtle and my partner is on one side of me, I find that if I have an arm close to my opponent's knees and I can keep a grip on the *outside* of either pantleg, they can't force a crucifix position without first breaking that grip. Plus, that grip might set something up for me such as a sit-through, a guard replacement (if I pick the outside of the knee closest to my face) or a double leg (if I pick the outside of the knee closest to my own knees). The crucifix player might still attack my other arm and there are plenty of other things they can still do to me, but no trapped elbow = no crucifix.
