All the many years of training, and education as a member of Lolthite society, as well as that of the societies he would be intended to infiltrate as a saboteur, and at the notion of these outsiders being his 'companions' and for that matter traveling WITH them, Sil's first thought was instinctually appropriate for his upbringing, one of disgust and displeasure, mentally questioning how these people were his 'companions', much less why he shouldn't harm them. His education was clear, they're the enemy, and their purpose an affront to Lolth. However, hardly a novice to the game of seeing advantages where others might not, these people could legitimize his desire to leave behind this life of being inferior to those who may even be of lesser ability, simply by the random luck of being born male, a matter he had little choice in. In that moment between thinking to question the order, and seeing how these outsiders may be useful, his thoughts less than guarded, he could be found to be not as willing a pawn of Lolth as his instructors and family thought.
Iejir, picking up on the thoughts upsetting his master, is less reserved and thoughtful before blurting out, "WHAT?! He wants us to travel with... with... urrrk!" Too late to stop Iejir, likely from offending the watchful psion, Silinrul snatches the imp off his shoulder, by the neck no less, angrily growling, "Venorsh! Ka dos z'klaen mai bauth ussta ssiggrins, tril dosst ooble'hwuen p'luin Usstan telanth, dkinoss Dorn edru ol ulu natha reibe!" Doubtless his new 'companions' may overhear most if not all of this, and while some may be shocked at the 'abuse' of his familiar, any aware of the nature of the creature, among the lowest form of Baatezu, it might come as little surprise that such extreme measures become necessary to keep the mouthy familiar from getting them both in trouble. The fist-strangle throat gulps with much effort, and unable to form a spoken word, Iejir nods to signal his submission and obedience, earning his throat released, and a freedom to return to his usual perch on that shoulder.
No longer to go separate ways from these outsiders, Silinrul turns about, and utilizes one of the more common enchantments on House Insignia, levitation, to leap, in a floating jump from his entry-point into the nest, and a graceful touch-down a short distance aside from Lothir, "It seems, my employer thinks you deserve an escort. I don't expect you to trust me, I'd think you all fools if you did. But, with me as your escort, you should have less difficulty getting past the gates." Like it or not, he's attaching himself to this group, per orders.