Why not? Anywhere, anytime, we are teaching a 24-hour practice. 24-hour practice. Why do we teach you to use mindfulness while grabbing doors?
It's not formal meditation, is it? When you are going to the bathroom, does anger always leave you alone and only attack you on the pillow? Do your future thoughts only come on the pillow? No. Of course, it is advisable to do Wise Reflection in informal situations.
Now the second part to the question, "also what do you think about including the people around us in the reflections?" Absolutely, yes. In fact we plan to talk more about this later. If you are on a bus, for a half-hour drive you could have, Compassion/Lovingkindness for each person in the bus.
Maybe you see a person who is blind, has a broken arm or another obvious Dukkha, you could also do Dukkha reflection seeing it externally and then bringing it internally, "Verily also my own body is of this same nature." Not just for those on the bus, also while you are looking out the window, what do you see as you are passing by? Use those moments anytime during the day. Externally, Internally. Use your daily experiences for benefit.
Inwardly or outwardly, externally or internally. What this person is referring to, "including the people around us in the reflections," this is what we call Outward or External Meditation, outward thinking. Inward means me, my world. Outward means everything outward, the whole world. So, when you reflect about the other people that is outwardly reflection. You can do both absolutely.