Visitors to the SkyDeck ledge up on Chicago’s Willis Tower — which is already scary enough as it is — got the fright of their lives on Wednesday when its protective layer cracked underneath them.

“There was a woman with two kids and they looked really pale and scared because the floor just cracked,” witness and fellow visitor Jesus Pintado told WBBM. “I’m scared of heights in general so when I saw that happen, I was like nope, not going on.”

Tower officials downplayed the incident, saying no one was in danger and that the protective layer did its job. The glass used to create the 103rd-floor walkway is supposed to hold up to 5 tons and the protective layer is meant to keep it from being scratched.

This is the second time that the top coating has cracked, with the other scare coming in May 2014. Tower officials said Wednesday that their engineers would be inspecting the floor to ensure its safety. Video posted online by Pintado shows the extent of the damage.

Attempts to reach Chicago’s Department of Buildings about the incident have been unsuccessful.