Whomever had the most chips at the beginning of the hand places best in the tournament.
The number of players or tables does not matter, it just the same as three people going all in on a single table and two bust out. Whomever had the most chips at the beginning of the hand places highest.
On the bubble the same thing, if there are 101 players left and ...
< TL;DR >
Bubbles and Hand-for-hand play are not the same thing, although hand-for-hand play is most often imposed right before the bubble bursts.
You shouldn't have 20 players over 4 tables, unless it's a 6-max tournament.
I wouldn't expect H4H to begin on the basis of any number of players being all in, just based upon the number of players remaining ...