actually in more ways than one, I worked for United and did pushbacks from the gate, but I think you mean the ATC bit.

What I remember from United the 'pits' / cargo bins that were closest to the engines were the best to transport 'Fluffy' your dog, not only for pressurization but HEAT.

IMO the vents should be out if very hot as well as the possible altitude change, so change in pressure.

frequency change approved , similar YMMV