A young mother, said to be in her early 20s, came up to the counter with her child to pay for a soda at an Alta convenience store in Arvada, Colorado on Sunday.
Montano said she was entertaining the baby when she made the observation.
"I was talking to the baby and she -- the girl -- had a glazed look on her face,” Montano told KUSA Wednesday. "I was asking her, 'Is everything OK?' I grabbed the baby’s arm, and (the mother) started to sway (and) she wouldn’t answer me. She was just lost in space."
Montano trusted her instinct to grab the baby -- and it was caught on surveillance video.
"So I thought I better take the baby, something doesn’t feel right. And then right there she started to fall, and I wasn’t sure still exactly what was going on, so I yelled at (a nearby) customer that was in the store (for help). She fell, I came back, grabbed the phone, called 911."
KDVR reported that Montano handed the baby to that same customer while she helped the woman.
"I’m a mother, I’m a grandmother. It’s motherly instinct to worry about children," Montano said.
Both the woman who had the seizure and the baby are reported to be doing fine.