Factual error: At the end, when Vanessa is thrown off the helicarrier, it's easily 200 foot down for her. Even if the tube is strong enough to survive that and all the debris falling on top of it, she's not strapped in, meaning she would smack every which way and probably break every bone in her body.
Factual error: When Deadpool is starved of oxygen, then causes an explosion, it is implied that the excess of oxygen, coupled with a heat source (match), causes the chain reaction which blows up the oxygen tanks. However, for a chain reaction to occur, fuel is also needed. Combustion is an oxidation of fuel. The only fuel present which is hot enough is the match. The hoses/ pipes and the tanks would not be flammable.
Answer: Yes that would be how she most likely was able to tell.