The vimuttayatanam The 5 bases of deliverance:
XXV. "Five bases of deliverance; here
.the teacher or a respected fellow disciple teaches a monk Dhamma.
And as he receives the teaching, he gains a grasp of both the spirit
and the letter of the teaching. At this, joy arises in him, and from
this joy, delight; and by this delight his senses are calmed, he
feels happiness as a result, and with this happiness his mind is
established [he attains nibbana];
b. he has not heard it thus, but in the course of the teaching
Dhamma to others he has learnt it by heart as he has heard it, or
c. as he is chanting the Dhamma... or
d. ...when he applies his mind to the Dhamma, thinks and ponders
over it and concentrates his attention on it; or
e. When he has properly grasped some concentration sign, has well
considered it, applied his mind to it, and has well penetrated it
with wisdom. At this, joy arises in him; and from this joy, delight,
and by this delight his senses are calmed, he feels happiness as a
result, and with this happiness his mind is established
Only e. is really related to some special mindstate. The other 4 ways(, a, b, c, d) of attaining Nibbana are based on directly considering the Buddha's teaching.
But could such consideration be done in the Belly Sandwich shop? I would say yes,.
Could it be done while sitting? yes
while walking? yes.
while defecating? yes.
and all the other situations described in the satipatthana sutta...
Should one think, while enjoying a sandwich at Belly sandwich shop "Oh this is not so good, I wish I was at the root of trees doing real practice!".
Or could there be there and then, at the very moment of ordering, or at the moment of seeing , or tasting, awareness of hardness or feeling, or mind with desire or mind with aversion....