Beyonce was caught in a real-life EMERGENCY on stage at her concert last night when her hair got tangled up in a stage fan -- and the crew scrambled to free the singer, MID-SONG!!!!!

Queen B was performing "Halo" in Montreal when disaster struck ... but like the PRO that she is, Beyonce continued to sing during the incident, NEVER ONCE MISSING A SINGLE BEAT.

Eventually, a crew member with a pair of scissors cut Beyonce free ... and she sashayed away from the devil equipment.

After the show, Beyonce posted a poetic note to her fans explaining the situation ... saying, "I got snatched."

In the end, Beyonce kept her composure throughout the entire ordeal ... and she just might be the toughest performer on the planet.