Presuming that the mafia actually do have a nightkill, and they can get it to go through tonight, we're in MYLO. So any information to help us direct a lynch is good.
We could claim something like "I could have prevented a night kill N1 and N2", "I didn't prevent it either night", etc. See who was roleblocked, who was jailed, who was doctored, and hopefully come up with some information from it. The two problems are:
1: This information won't be reliable. Even if we could be 100% certain claims are true, we can't be certain that it led us to a lynch, and we can't even be certain of the claims being true.
2: This information can help direct mafia's kills at night. This IS an issue, as mafia seem to be having issues properly directing kills (or have declined to attempt to, or have no nightkill.) If we can guarantee that claiming would lead to a mafia lynch, it's worth it.. but is it worth it given that a claim doesn't guarantee that?