Aeiyan's arrow hit the hobgoblin on the right* square in the groin, at a spot not protected by its ring mail armor.
[*since the one on the left just retreated into the cave, there is only one hobgoblin left visible at the boulders, so I just assumed you would target that]
In an effort to continue supporting Bartleby's deceits, he shouts, "One of them got away!" -- then moves his speed (35 feet) toward the enemy. He pulls out another arrow as he moves, but does not nock it yet.
(Aeiyan was farther than 100 feet from the hobgoblins, because he was hiding in the woods behind the Dancing Lights. I'm sure this takes him out into the open, but I don't know how far. Please pick a likely number.)
You are 2 move actions from the boulders
Bartleby and
Reijik are also running or charing towards the hobgoblins, and they are too at 2 move actions left to get there.
Tock and
Sulannus are still among the trees, let's say 3 move actions from the cave entrance.
[Basically the whole charge is going to take an extra move from the Dwarf compared to all the others]
I checked the rules for the
Charge action, and [MENTION=6749529]Jimmy Disco T[/MENTION] is right IMO. It's a regular action, so before (or after) the Charge action, a move at normal speed is possible. The Charge action itself is a move+attack at the end, but the move must be minimum 10ft and maximum half your speed.
But... the boulders basically cover the lower bottom of the cave entrance itself, and I figure them being between 4-5ft high, so I don't think charging directly against the hobgoblins is possible. Although, if you really want to (since you have a reach weapon), and if the last hobgoblin is still there and alive

we can figure out how to represent such stunt.
For everybody, the boulders have been clearly put there for protection, both to provide cover and to block or at least slow down potential threats. I can anticipate that it will cost you a move to pass to the other side of the boulders, but the brave can attempt a jumping (Strength/Athletics) or quick-climbing (Dexterity/Acrobatics) to instantly get on top (failing the check equals wasting a move action or something similar).