Talk:Stalker/@comment-25320309-20140830181834/@comment-74.75.3.109-20140831030136

The first one, except the bonus is per player in the squad/cell at all (whether they are marked or not), with marked teammates being additional chances for him to spawn.

As for 3.5% it later claims in the article, my thought on that is that the chance is assuming a full squad/cell, with the "per player" part being the additional chances for him to spawn like I already mentioned.