I think they're overestimating mossads abilities. There's no way they have access in Russia the way they do in the Middle East. They're also not going to try something as abrasive as a nuclear missile. They would lose that fight 100% of the time. But mossad is good at carrying out assassinations, and bad about hiding who it was. My guess is she means assassinations. But mossad would be much more noticable in Russia than in tehran.