If you have the bounding box the enclosed area and the position of the wheelchair, then you can use the following code to check whether the wheelchair is inside the enclosed area:
Code:
# bb is bounding box of enclosed area
# p is [x,y,z] position of wheelchair
if (bb.xmin <= p[0] <= bb.xmax) and (bb.ymin <= p[1] <= bb.ymax) and (bb.zmin <= p[2] <= bb.zmax):
print 'Wheelchair inside'
else:
print 'Wheelchair outside'