An NBC reporter's stunned reaction during the White House shooting scare is going massively viral ... with social media users already turning the moment into memes. NBC News correspondent Julie Tsirkin was filming outside the White House Saturday when multiple gunshots suddenly rang out nearby. In the now-viral clip, Tsirkin freezes mid-report and asks, "What is that?" as loud pops echo through the area behind her. Her cameraman initially guessed the sounds were fireworks ... but seconds later,