Joseph,
A child is being abused often and you have seen it more than once. You are asked to testify against the abuser and when you do the child will stop being abused and be safe. If you do not testify the abuser will not stop what they are doing.
Which do you choose, Stopping that child from being abused and lose your Olam Habah and testify or do you not testify, the child will continue to get abused and you will maintain your olam habah for not testifying