A person who looks fine from outside, is not always OK inside.
I don't know if these persons were forced to deplane, but, if they were willing to stay on the ground, then let them be. Maybe, it was a panic attack. Who knows ?
Similar to what happened to another poster, I was also repatriated once by plane. I was fine, but insurance obliged me to lay on a stretcher ...
First time ever, I had 6 boarding passes in hand ... With the medic, the nurse and my spouse, we occupied 3 rows of 3 economy seats for a two-hour flight ...
(For those curious, 3 rows of 2 seats were folded, and the stretcher was fixed over them, at the rear of a A320)
Again, I was feeling perfectly fine ...