Kurt has just enough presence of mind to latch himself around a metal post on the railing as they take off. Moving away from the Earth is what's messing him up, his own teleportation ability works on him knowing on some level where he is on the planet at all times. Without that, his equilibrium is completely off kilter. Enough that it's trumping the drugs in his system...and making him feel very ill indeed.
He groans, unwilling to let go of the railing or move from where he is curled around the post. "...mein headt....ow..." He's got a dandy headache, probably from fighting back against Stryker's serum. Kurt looks up at the Doctor, looking a little green...figuratively. "I...I do not feel vell..." Talking in whole sentences was an improvement.