Lukasz Robert Pawlowski, 33, appeared in the dock on the sex assault charge when he asked to leave the dock to go to the toilet.
But when he returned he “slashed wildly” at his throat – and collapsed in a bloody heap at Haverfordwest Magistrates Court in Pembrokeshire, West Wales.
Ambulance workers and a helicopter were called to the court to treat badly injured Pawlowski are on the scene.
One witness who was in the court said: “He came into the dock, then asked to go to the toilet.
“He went out, came back, muttered something then started slashing at his throat.
“The court room was then cleared out, and first aid was given by paramedics in the dock.
“I’m not sure if he lost consciousness but he did lose a lot of blood.
Pawlowski, of Bush Street, Pembroke Dock, West Wales, pleaded guilty to sexual assault in December and was due to be sentenced today.
He had been banned from entering the shop, which cannot be named, after groping the woman worker in October.
The court earlier heard Pawlowski gestured to the woman to kiss him when he walked into the shop where she worked on October 30.
After she declined he leant towards her, grabbed her wrists and kissed her on the cheek, then walked off into the store.
Pawlowski later grabbed her from behind while she carried cans of lager across the store.
Alex Scott, prosecuting, said: “He pulled her backwards and proceeded to kiss her on the lips.
“She went back to the counter and told him he had no right to do that.”
The incident was captured on CCTV and Pawlowski was arrested two days later. He told police he had kissed her, but it was a question of ‘mixed messages’ as he thought he had her consent.
A victim impact statement read to the court said: “The incident made me fell dirty and I feel vulnerable in work now. It impacted on my job, and I don’t feel I can work nights.”
She added: “I’m still fearful of seeing him, and avoid Bush Street in case I see him.
“I still get scared and concerned whenever I am on my own in the shop. I don’t know if I can carry on working there in fear.”
He originally denied the offence but later changed his plea to guilty.
Dan Griffiths, defending, said: “It is quite clear that the defendant makes a wise choice in terms of his terms of plea having seen the CCTV.”
He added: “It is nothing more sinister than kissing the complainant on her face.”
Magistrates adjourned sentencing for a probation report and Pawlowski was released on bail until today with the conditions not to contact the complainant or enter the shop.
A spokesman for Haverfordwest Magistrates Court said: “The ambulance service are still here working on him at the moment.
“We do not know yet how serious the injuries are or what the situation is regarding other cases listed for the day.”