Tbh I think if this genuinely happened and I just found out right now, I would just start walking and not stopping. I would think I'd be the most mindful and alert I have ever been in my life and I wouldn't want to waste that. I also imagine I would also probably be extremely nice to everyone. Like someone's walking in the rain or something and I'd just hand them the coat I was wearing for them to keep. It would look really weird lol but I think that's the kind of hyper-selflessness that you'd just do without even a thought if you knew you were about to die.

Thanks for asking this question btw it's very intriguing. It makes me wonder if it's even remotely possible to live each day like it's your last y'know.