I think “absolutely obliged” is a bit of an extreme term to use here. If there is an aggressor you should run whenever possible because you don’t know what may happen to you if you engage in combat. Unless you are some Marine level fighter I would steer clear of any potential fighting. Generally if you are alone, try and slow down the attacker first before taking off. If with grandparents and they are unable to run, then personally I would stand my ground until the police comes, but if caught in such a scenario, don’t immediately engage the aggressor physically. If they’re clearly superior in ability to you or has a knife, ask what he/she wants. If they just want money, then you’d better give it to them because your life is way more important than money. Normally an aggressor would be reluctant to kill, so if you are unable to run, find out what they want first. Not saying that you should ALWAYS cede to their demands, it has to be within reason of course. If it’s something like money, a watch, or piece of jewellery then give it to them. If they’re asking for your bank account, house or children then hell no.