Darshit Tanna was sentenced to 18 months in prison after sexually assaulting a female paramedic
Darshit Tanna "grabbed" the woman twice – and also attacked a male colleague who tried to intervene.
The 28-year-old then fled the ambulance before being arrested.
A judge slammed Tanna for assaulting "a person doing their great public duty".
Derby Crown Court heard how the incident took place in the city on June 7 last year.
Paul Gibbs, prosecuting, said an ambulance was called to a probation office in when staff became concerned about Tanna's behaviour while he was sitting in the reception area.
Mr Gibbs said: "He was completely silent and uncooperative and an ambulance arrived. The female paramedic was sat in the back with him and he was just staring at her making her feel uncomfortable.
"He sat fixedly staring at her then made a grabbing motion towards her making contact with her right breast. She called a male paramedic to help her and he got between the two of them but the defendant reached around him and grabbed the female paramedic's breast for a second time."
Darshit is believed to have grabbed the female twice and also tried to attack her male colleague
Tanna escaped the ambulance but was arrested nearby. He refused to answer questions when interviewed by police.
However, he later pleaded guilty to sexual assault and a second count of assaulting the male paramedic.
Judge Jonathan Bennett, sentencing, said: "What you did was quite deliberate. She felt uncomfortable and you were very eager to grab her.
"She was, like all of our public servants, just doing the great job that they do for us and had come to assist you. Now this sexual assault has long term effects and consequences on the lady concerned."
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A court judge claimed Mr Tanna grabbed the female's breast as she sat with him in an ambulance
In an impact statement that was read to the court, Tanna's victim told how being "grabbed" in the "confined space" of the ambulance left her devastated.
She added: "My life has changed as a result of this incident. I feel humiliated, dirty and vulnerable.
"This has caused huge distress and upset and the emotional effect of what he did to me has affected my personal and private life.
"I have sleepless nights and flashbacks and I no longer feel safe in confined spaces. What he did to me will live with me forever."
Darshit firstly refused to answer questions by police but later pleaded guilty to sexual assault
Steve Ramsell, defending, said Tanna claimed he couldn't remember the incident. Speaking after Tanna was jailed, Mark Ward, a security specialist at East Midlands Ambulance Service, said: "Our staff work hard every day to deliver the best possible care to the public we serve. Actions like this make their job even harder and we will always take action where we can.
"We have a zero-tolerance approach to any level of abuse or assault against our staff. The local security management specialist team worked with the staff to support them through the process of giving evidence and with police and the Crown Prosecution Service to ensure the defendant received the appropriate punishment."