5 times WWE was forced to break kayfabe 

#2 WWE broke kayfabe to provide updates on Jerry Lawler following his on-screen heart attack

It was one of the scariest nights in WWE history on September 10, 2012. WWE color commentator Jerry Lawler suffered a near-fatal cardiac arrest whilst commentating with Michael Cole. Lawler had featured in a match earlier in the night, but began to wheeze and breathe heavily whilst sitting at the announce desk before collapsing. WWE medical personnel immediately attended to him.

WWE panned to Michael Cole after the incident and broke kayfabe to provide the news that "The King" had collapsed. He confirmed it was not part of the night's presentation and there was no further commentary for the rest of the show. Jerry Lawler later made a recovery and survived after suffering a cardiac arrest.

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#1 WWE commentator broke kayfabe to announce Owen Hart had passed away

Tragedy struck at the Over the Edge pay-per-view in 1998. Whilst Owen Hart was due to make a grand entrance from the rafters, the safety latch gave way and Hart fell into the ring. The incident occurred just prior to his match and a video promo was being aired in the arena and to fans at home.

Despite the incident, Vince McMahon declared that the show must continue despite the heartbreaking situation.

Later in the show, the camera crossed to Jim Ross at the commentary table who announced that Owen Hart had died. Ross reiterated that this was a real-life incident and Owen Hart had tragically passed away.