"The most common side effects with OsmoPrep [and others I looked up] are abdominal bloating, abdominal pain, nausea, and vomiting"
Pt with anxiety(causes nausea) before colonoscopy ingests bowel prep(common side effects include nausea, vomiting, and pain), and experiences an episode of isolated vomiting.
Plus, while this patient may receive EKG in the hospital, we are talking about the field.
It seems you missed a few things about the OsmoPreP.
Oral sodium phosphate (OSP) solutions, including FLEET, Visicol and OsmoPrep, draw water into the gut to promote cleansing. They may be easier to tolerate, but can cause dehydration and electrolyte imbalances. A high phosphate load may also not be safe for patients with kidney, heart, liver, or certain intestinal diseases.