In dire need of money, Mr. R decided to steal from his next-door neighbor, Mrs. V. On the night of May 15, 2010, Mr. R proceeded with his plan entered Mrs. V's bedroom by breaking one of the windows from the outside. Finding Mrs. V sound asleep, he silently foraged through her cabinet, and stashed all the bundles of cash and jewelries he could find. As Mr. R was about to leave, he heard Mrs. V shout, "Stop or I will shoot you!", and when he turned around, he saw Mrs. V cocking a rifle which has pointed at him. Fearing for his life, Mr. R then lunged at Mrs. V and was able to wrest the gun away from her. Thereafter, Mr. R shot Mrs. V, which resulted in her death. Mr. R's deeds were discovered on the very same night as he was seen by law enforcement authorities fleeing the crime scene. May Mr. R validly invoke the justifying circumstances of self-defense? Explain. (2019 BAR)