A friend of mine recently posted about the following situation:
Alice is on public transport when she is approached by Bob, who asks her unwanted questions (e.g. where do you live, do you want to go out with me this weekend, etc). Alice attempts to avoid Bob by alighting, but Bob alights as well and keeps talking. Can Alice call the police? What about an uninvolved third party? If it matters, Bob is unarmed and the country is Singapore.
My original inclination is "yes". However it looks like calling the police worldwide should only be done in emergency situations, e.g. the Singapore police website says one should only dial 999 when a crime is in progress, someone is hurt or in danger, and so on. Bob in this situation hasn't actually become violent, and while Alice is understandably frightened, she isn't actually in danger.
If the answer is "no", how should Alice shake off Bob? "Walk to a police station" seems like the obvious answer, but there might not be one nearby.