“If they believed they were getting a shot that could cause that.”
If that is possible, then show us how many people given placebos, in the thousands of clinical trials that have already been performed, just dropped dead after being given a placebo.
Shouldn’t be hard to find that evidence if the phenomena you are asserting is actually a real thing and not a figment of your imagination.
How many people participate in clinical trials when they believe the shot will probably kill them?
Do they screen for suicidal participants?