Just after 20:00 GMT they heard a rumbling sound, but dismissed it as a passing bus.
Only later would Robyn realise it was the first bomb detonating at the nearby Mulberry Bush, at the base of the Rotunda building.
Minutes later, the Tavern went black.
“There isn’t a sound when you’re that close to a bomb of those proportions,” she said.
“It overtakes your whole body. It’s a vibration, but it’s not a fast vibration. It’s a deep underground sort of vibration that goes through your body.”