When Richard sees the coin and travels back to the future/out of his hypnosis? Did Elise see him just disappear, disintegrate, spontaneously combust? Not that it really matters. I'm just curious.
Whether she saw him fade away or spin into some vortex, the bottom line is she saw a human being disappear in front of her eyes. An extremely disconcerting event to say the least. It's no wonder her career was derailed. The questions and confusion must have been enormous.
I'd also like to think he dropped the penny as he disappeared.