in PPEH was shown C-like metal tubing to adapt a hose to be lead over in a passenger cabin. because rubber hose can melt from high temperatures coming from a tailpipe a hose on exhaust tube should be connected on adapter which absorbs excess of heat, open ending of this adapter for hose connection can be stuffed with activated coal filter and some inert porous materials for smoke filtering therefore theoretically you can attach a hose from exhaust pipe directly to oxygen mask and die in couple of minutes without feeling of suffocation, caveat is beside carbon monoxide modern engines give carbon dioxide(it cause smothering via hypercapnia response) and nitrous oxides which converting in nitric acid in lungs causing lung tissues burns