There were a few retarded instances in that scene:
1. Elena successfully blocked the door against Kol for 8 seconds. It's funny when Kol kicked in the doors it looked like he needed to put in effort given what we've seen Elijah has done with a casual pebble/coin toss (never mind the physics).
2. When Elena speeds in to save Jeremy, she actually overpowers Kol, and continues to press his arm against his body. Sure he had a cleaver in his shoulder, that shouldn't have stopped him from bitchslapping her across the kitchen. This went on for 10 seconds.
Kol pretty much got beaten by two noobs. The "trap" isn't really an excuse because there was no freaking trap, it was just invite him in and try to kill him.
Kol did make a stupid mistake though, he kept the white oak stake on his person. He should've kept it hidden somewhere safe since he didn't really need to use it, and given how easily even Originals can be blitzed, it ends up being a risk against himself.
Kol's problem was that he constantly underestimated Damon, which is why Damon was able to get the drop on him multiple times, but then usually beaten senseless moments later...but Kol dying like he did was just horrible.
They could have at least given Jeremy a big push in power, ala Alaric for it to make sense for them to be able to kill him, but oh well. Story supercedes logic. Klaus and Elijah are pretty much the only ones to actually display their power as originals.