The 300 guests at Monday's Magen David Adom UK dinner in central London heard from an MDA volunteer paramedic called into emergency action in Jerusalem last week.
Lawyer Aaron Adler said he was "first on the scene when a terrorist stabbed a policewoman in the Old City.
"Leaving my office, getting on my bike and doing what needed to be done. Then - as is so often the case - being ready was the difference between life and death."
The dinner, which raised a record £2 million, was also addressed by MK Avi Dicter on the threats facing Israel. The theme of the evening was "Always Ready" and diners were shown how donations from around the world enabled MDA's 14,000-strong team to be prepared for any situation.