I am following orders that I am unable to discuss at this time. [ which is the truth. she's under orders from captain picard to keep what she's doing between the starfleet personnel present. and during those few seconds that she's turned away from her tricorder to say this to xander, that bot she was following has zoomed right up to them and trapped them in one of those force fields.
seven sees this as an opportunity to try and gather readings on the force field, which clearly the bot disapproves of. ]