What happened in the Derelict ship, what caused this hole?

Well, I suppose one might expect some damage to the ship, which we will probably find on the spacecraft that David and Shaw crash landed with.

Considering the floor is level and there's no obvious internal damage (hole in floor aside) unlike the Juggernaut, I'd side with 'landed' over 'crashed'.

In that case I suppose the only scenario is this: The Jockey gets attacked by a facehugger during "normal" flight. He wakes up in time for landing, knows something's wrong and sends a warning signal, and just when he's landed the chestburster pops out?

my theory is the engineer is facehugged in cryo sleep. once the process is over he comes to without any knowledge, like kane in alien, and believes he has just come out of cryo sleep naturally. he goes to the pilots chair to do whatever it is he wouldv done normally. the impression im given from alien is that the derelict crashes due to the chest burster erupting from the SJ's chest and that the creature creates the hole to escape/ get out of the ship possibly after it has crashed, or to find somewhere secluded to molt. the signal way be a preset warning and the SJ only had to push a single button once he realised what was happening. or again, a pre set warning for that type of ship incase of crashlanding due to the nature of its cargo. im sure the time it would take to mount a rescue the engineers would know the xeno would have established a nest and be fully grown and they surely are smart enough to avoid confrontation with that situation, so they just decide to leave it undisturbed