A deranged Long Island woman is facing up to 25 years behind bars for tossing a homemade dynamite stick at her sleeping boyfriend — whose hand was blown off as he tried to get rid of the explosive, officials said. Keyonna Waddell, 35, was found guilty Friday on charges stemming from the March 2024 incident that turned violent after the two got into an explosive argument, the Suffolk County District Attorney’s Office said. Keyonna Waddell, 35, threw a homemade stick of dynamite into her now-ex’s room while he slept. “Domestic violence can escalate to deadly levels, and this case is a sobering reminder of that reality,” DA Ray Tierney said on Friday after the guilty verdict. Waddell had threatened to use dynamite against her then-boyfriend multiple times in the months leading up to the incident, but he never expected his lover to follow through on the threat, the DA said.…