In Aliens, did Burke have a plan at the end?

Burke was most likely just hauling ass as fast as he could to the landing pad, just as Ripley and Hicks were doing after Newt got taken. Although nowhere in the compound was really safe anymore, Burke probably (incorrectly) thought that shutting the doors behind him would at least slow down the Xenomorphs.

When he fled, he fled through the medical area, but he certainly didn't stop to pick up any critical data, samples, etc. while there. I think bringing specimens/samples back was the last thing on his mind given his panicked state.

Just before the massed Alien attack on the operations center even Hicks had come around to the idea that Burke had to be killed.

RIPLEY: You know, Burke, I don't know which species is worse. You don't see them fucking each other over for a goddamn percentage.

HICKS: All right, we waste him. No offense.

And then the Aliens cut the power. Ripley still wanted him alive, but Burke had to believe his chances of survival were poor remaining with the marines, who all wanted his blood. So the first chance Burke got he put distance between himself and the marines, hoping that the Aliens would take care of the marines for him. That would leave only Bishop, who presumably would submit to Burke's authority. At that point Burke might be able to salvage something of his personal mission. With Alien DNA splashed liberally around the compound (the things drip slime everywhere) Burke might be about to scrounge a sample, but at worst he'd save his own crafty skin.

Burke's plan was to escape alive and make sure all witnesses against him were dead. I do not think he had any idea how that was going to work and was running in blind panic.

It is not as if he had any time to think between Hicks wanting to kill him, Ripley wanting the prosecute him and lights going out and the attack starting. He managed to distract Gorman so he could run and lock the doors behind him but that was as far ahead as he had planned.

Well... Burke was probably thinking the Marines might waste him for his treachery. He was almost as much an enemy as a xenomorph to them at that point, and they might well have if Ripley hadn't been there.

His plan, it seems, was just to get away from the Marines/aliens and hide, and probably to try to reach Bishop. If he had survived and got to the dropship before the others, I reckon he would have ordered Bishop to leave them behind, or lied that they were dead or dying.

Burke was only interested in himself, so the plan would have involved his immediate survival and covering up the truth of what he'd done.