Actually, the action of "jumping out" seems to me to be the orcs actions for the surprise round. They are hidden behind some wall or boulder, and do a switch or a move to reveal themselves. End of surprise round, roll initiative…
Which has, of course, been the difficult thing about Surprise rounds since 3E.
As an ambusher, in the surprise round you can:
a) Jump out (move action) and do nothing
b) .... I can't think of a b)
Fire a missile weapon? Blast with a spell?
This.The players are surprised because the orcs jumped out, not surprised and then the orcs jump out. That's how it makes sense to us at any rate.
Which has, of course, been the difficult thing about Surprise rounds since 3E.
As an ambusher, in the surprise round you can:
a) Jump out (move action) and do nothing
b) .... I can't think of a b)
Which has, of course, been the difficult thing about Surprise rounds since 3E.
As an ambusher, in the surprise round you can:
a) Jump out (move action) and do nothing
b) .... I can't think of a b)

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.