Suicide mechanisms are used after the mission has failed, either they are captured or about to be captured. Agents aren't going to use a suicide option while still able to operate. (Although an actor free to operate but for which there isn't a survival option may choose a suicide attack. There was an American kamikaze in WWII, he wasn't going to make it back to the carrier, the only possible rescue was the very fleet he was attacking.)
When it comes down to a quick death by a suicide agent vs being tortured and then likely an unmarked grave it can be a reasonable option. Agents which aren't so likely to be put through the wringer and might be exchanged are another matter--Gary Powers had little reason to use his suicide option. He didn't have great secrets to be tortured for.
When it comes down to a quick death by a suicide agent vs being tortured and then likely an unmarked grave it can be a reasonable option. Agents which aren't so likely to be put through the wringer and might be exchanged are another matter--Gary Powers had little reason to use his suicide option. He didn't have great secrets to be tortured for.